首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   158篇
  免费   16篇
林业   12篇
农学   2篇
  40篇
综合类   8篇
农作物   2篇
水产渔业   22篇
畜牧兽医   54篇
园艺   6篇
植物保护   28篇
  2024年   1篇
  2023年   1篇
  2022年   2篇
  2021年   7篇
  2020年   7篇
  2019年   7篇
  2018年   4篇
  2017年   3篇
  2016年   9篇
  2015年   7篇
  2014年   7篇
  2013年   5篇
  2012年   13篇
  2011年   16篇
  2010年   11篇
  2009年   10篇
  2008年   17篇
  2007年   10篇
  2006年   8篇
  2005年   11篇
  2004年   4篇
  2003年   10篇
  2002年   3篇
  2001年   1篇
排序方式: 共有174条查询结果,搜索用时 31 毫秒
51.
Objectives: Our objectives were to describe an endoscopic technique of the navicular bursa, describe the endoscopic anatomy, assess its feasibility on live horses undergoing an exploratory endoscopy, and assess the usefulness of standard arthroscopic instruments introduced via a contralateral portal.Study design: This was an anatomic study on cadaver limbs and endoscopic observation on clinical cases associated with problems of the navicular bursa and/or navicular bone.Animals or sample population: The sample population was 4 cadaver forelimbs of 2 horses weighing 300 to 450 kg and 8 live horses and one pony weighing 180 to 550 kg with navicular bursa disease.Methods: One cadaver limb was left untouched; the 3 others were dissected in a different way. Dissection and endoscopy of the navicular bursa were performed on the cadaver limbs with 4-mm and 2.7-mm 30° forward oblique arthroscopes. Relative positions of the arthroscope and of various arthroscopic instruments in the bursa were observed. Then, exploratory endoscopy of the navicular bursa was performed on live horses suspected of navicular bursa disease after clinical, radiographic, and/or sonographic examination. Visualization with saline solution and carbon dioxide was compared. Standard arthroscopic instruments were introduced according to the lesions observed. Some lesions were treated and a lavage of the navicular bursa was performed in all horses. Postoperative recovery was followed until 3 months after surgery.Results: Most parts of the anatomic structures of the navicular bursa could be observed with the 4-mm or 2.7-mm arthroscope, and standard arthroscopic instruments could be introduced into the bursa. A lavage of the bursa could be performed in all horses and no iatrogenic damage or postoperative complications were noted.Conclusion: Endoscopy of the navicular bursa with standard arthroscopic instruments is a feasible technique in horses and could be a useful diagnostic modality in suspected disease of this area.Clinical application: Diagnostic endoscopy in horses suspected of navicular bursa disease can be used to complement other diagnostic means. It already is used for treatment of septic bursitis; endoscopy of the navicular bursa could have other therapeutic applications in the future.

Introduction

Arthroscopy of the dorsal aspect of the distal interphalangeal joint in horses was used for removal of extensor process fractures and for diagnosis examination of this joint.1 Arthroscopy of the palmar (plantar) aspect of the distal interphalangeal joint was described for removal of fibrin, intra-articular lavage in septic arthritis, and to access some fractures of the distal sesamoid (navicular) bone and middle and distal phalanges.2Endoscopy of the bursa podotrochlearis (navicular bursa) was recently described for treatment of septic bursitis.3 In this procedure, the instruments were mostly introduced through the original penetrating wound at the frog and through the flexor digitorum profundus (deep digital flexor tendon). In another study,4 the authors observed the navicular bursa in cadaver limbs and compared the endoscopic observation with pathologic findings.Lesions of the navicular bursa and contiguous anatomic structures (deep digital flexor tendon, palmar/plantar fibrocartilaginous facies flexoria [flexor surface] of the navicular bone, ligamentum sesamoideum distale impar [impar ligament], and ligamenta sesamoidea collateralia [collateral sesamoidean ligament]) can be associated with navicular syndrome.5, 6 and 7Conventional radiographs allow evaluation of osseous lesions of the navicular bone (loss of cortico-medullary definition, irregularity of the sagittal ridge of the facies flexoria, and irregularity or thickening of the flexor cortex)5, 8 and 9 but are less sensitive for soft tissue evaluation.Ultrasonography allows the evaluation of some soft tissue lesions.10 It can be performed at the palmar aspect of the pastern or by a transfurcal approach.Scintigraphy is more sensitive than radiography in the evaluation of navicular syndrome, and it can complete an inconclusive radiographic examination.11Magnetic resonance imaging (MRI) and computed tomography (CT) scan are also valuable diagnostic means for navicular syndrome in revealing some osseous abnormalities undetectable with conventional radiographs8 and 12 and, for MRI, in providing a reliable evaluation of soft tissues.13, 14 and 15The objectives of this study were to document an endoscopic approach to the navicular bursa, describe the endoscopic anatomy, assess the usefulness of standard surgical instruments introduced via a contralateral portal (which could have potential benefits in diagnosis or treatment of lesions in this area), and finally, to assess the feasibility of this technique in live horses undergoing an exploratory endoscopy.

Instrumentation

The procedure was performed at 2 different clinics with different sets of instruments. Equipment used included two 4-mm (Dyonics or Storz) and one 2.7-mm (Optomed) 30° forward oblique arthroscopes connected to a light cable (Optomed or Storz) and light source (Stryker or Storz). The arthroscope was connected to a camera (Stryker or Storz) and a video system, which allowed recording and printing of endoscopic views. Various surgical instruments were used: a blunt tendon knife for splitting surgery, motorized synovial resector blades (Dyonics), straight and curved curettes (Sontek), Basket type synoviectomy forceps (Acufex), and Ferris-Smith rongeurs (Sontec).

Procedure

Cadaver limbs

Four distal forelimbs from 2 French Warm Blood equine cadavers weighing 300 to 450 kg with no lameness history were examined. Radiographs of the navicular bone were previously performed to document the absence of preexisting lesions. Three views were used: Dorso (60°) proximal-palmarodistal oblique, lateromedial, and palmaro (45°) proximal-palmarodistal oblique.The first limb was partially dissected (skin and subcutaneous tissue were removed) and the navicular bursa was examined by introducing the 4-mm arthroscope lateral to the deep digital flexor tendon.Navicular bursa endoscopy was performed in a similar way on the second undissected limb. The procedure was recorded on videotape and endoscopic photographs were printed. Various instruments were introduced by a medial approach, symmetrically to the arthroscope portal.The third limb was partially dissected like the first and cut in a sagitttal way with a sharp circular saw. The 4-mm arthroscope was introduced into the bursa and its progression from the skin to the bursa was observed by a sagittal view (Figs 1 and 2).
Full-size image (53K)
Fig. 1. Third dissected limb cut in a sagittal way. The 4-mm arthroscope is introduced into the digital sheath and its progression to the navicular bursa is observed. DDFT, Deep digital flexor tendon; Ds, digital sheath; Mb, separating membranes (Ds synovial layer + connective tissue + Nb synovial layer) between the digital sheath and the navicular bursa; Nav, navicular bone; Nb, navicular bursa; P2, 2nd phalanx; P3, 3rd phalanx.
Full-size image (55K)
Fig. 2. Same limb as in Fig 1. Sagittal view of the 4-mm arthroscope introduced lateral to the DDFT into the navicular bursa. DDFT, Deep digital flexor tendon; Ds, digital sheath; Mb, separating membranes (Ds synovial layer + connective tissue + Nb synovial layer) between the digital sheath and the navicular bursa; Nav, navicular bone; Nb, navicular bursa; P2, 2nd phalanx; P3, 3rd phalanx.
The limb was flexed and anatomic modifications were observed.The fourth limb was dissected; skin, subcutaneous tissue, distal digital annular ligament, digital sheath, and the tendon of the flexor digitorum superficialis (superficial digital flexor) were removed at the palmar pastern level. The hoof, the palmar part of the cartilaga ungulara (ungular cartilage), and the bulbs of the heels also were removed. The tendon of the deep digital flexor was transversally cut at half-pastern level and reflected distally to expose the narrow synovial structures (both digital sheath and navicular bursa synovial layers and connective tissue) separating the digital sheath from the navicular bursa.First, the arthroscope was introduced laterally and various instruments were introduced medially. The portals and relative axis of the arthroscope and instruments were observed in a proximo-distal view (Fig 3).
Full-size image (51K)
Fig. 3. Fourth dissected limb. The tendon of the deep digital flexor tendon is transversally cut and reflected distally to expose the synovial membranes separating the digital sheath from the navicular bursa. The arthroscope is introduced laterally and various instruments are introduced medially. DDFT, Deep digital flexor tendon; Ds, digital sheath; Mb, separating membranes between the digital sheath and the navicular bursa.
Then, the synovial structures separating the digital sheath from the navicular bursa were removed and the position of various instruments on the fibrocartilaginous facies flexoria of the navicular bone was observed (Fig 4).
Full-size image (51K)
Fig. 4. Same limb as in Fig 3. The synovial membranes separating the digital sheath from the navicular bursa is removed and the position of various instruments on the fibrocartilagineous facies flexoria of the navicular bone is observed. DDFT, Deep digital flexor tendon; Coll, collateral sesamoidean ligament; Ff, facies flexoria of the navicular bone; Imp, impar ligament.

Animals

An exploratory endoscopy of the navicular bursa was performed on 8 live horses and a pony from 4 to 12 years of age weighing 180 to 550 kg. These horses presented clinical and radiographic or sonographic signs of navicular bursa disease associated with lesions of the navicular bone or the distal interphalangeal joint. These cases are shown in the Table.  相似文献   
52.
The shea tree, Vitellaria paradoxa, is one of the most economically and culturally important indigenous tree species in the Sudano-Sahelian region. Its seeds contain a vegetable fat, internationally known as shea butter, which is widely used in edible, cosmetic and pharmaceutical sectors. Based on samples from 456 trees distributed in 17 locations across the species natural range from Senegal to Uganda, the fatty acid and tocopherol variation, and its relationship with geographic and climatic variables, was assessed in order to address the pattern and the origin of this variation across the natural range. Significant differences between Western and Eastern regions for oleic, stearic acid, saturated–unsaturated acid ratio and γ-tocopherol were identified that it is postulated maybe a result of genetic drift due to the evolutionary history of shea tree populations. Within regions the difference among stands was significant for most constituents; however the major part of the variation was observed among trees within stand (53–90 %). Relationships with climatic variables were not verified, weakening evidence for clinal variation hypotheses suggested by previous studies.  相似文献   
53.
Gene flow between cultivated and their wild relatives is one of the main ecological concerns associated with the introduction genetically modified (GM) cultivars. GM sorghum cultivar has been developed and its commercial production may be possible in the near future. The rate of gene flow depends on the fitness of wild × cultivated sorghum hybrids. The study aimed at estimating adaptive values of wild × cultivated sorghum hybrids in generations F1, F2, and F3 compared to their parents. Artificial crosses of four wild sorghums, five cultivated sorghums, and two male sterile lines were made to produce the F1 generation, which were advanced to F2 and F3. Each hybrid generation and their respective parents were evaluated for their adaptive value at two sites in a randomised complete block design with seven replicates. The resulting progenies did not show serious fitness penalties. Some hybrids were as fit as their respective wild parents and no consistent differences exist between the three generations studied. Thus, the resultant wild × cultivated hybrids may act as avenue for introgression.  相似文献   
54.
More than 30 epiphytic lichens, collected in Agadir (Morroco) and along a 150-km transect from the Atlantic Ocean eastward, were analyzed for their metal content and lead isotopic composition. This dataset was used to evaluate atmospheric metal contamination and the impact of the city on the surrounding area. The concentrations of Cu, Pb, and Zn (average ± 1 SD) were 20.9 ± 15.2 μg g−1, 13.8 ± 9.0 μg g−1, and 56.6 ± 26.6 μg g−1, respectively, with the highest values observed in lichens collected within the urban area. The 206Pb/207Pb and 208Pb/207Pb ratios in the lichens varied from 1.146 to 1.186 and from 2.423 to 2.460, respectively. Alkyllead-gasoline sold in Morocco by the major petrol companies gave isotopic ratios of 206Pb/207Pb = 1.076–1.081 and 208Pb/207Pb = 2.348–2.360. These new, homogeneous values for gasoline-derived lead improve and update the scarce isotopic database of potential lead sources in Morocco, and may be of great value to future environmental surveys on the presence of lead in natural reservoirs, where it persists over time (e.g., soils and sediments). The interest of normalizing metal concentrations in lichens to concentrations of a lithogenic element is demonstrated by the consistency of the results thus obtained with lead isotopic ratios. Leaded gasoline contributed less than 50% of the total amount of lead accumulated in lichens, even in areas subject to high vehicular traffic. This strongly suggests that the recent banishment of leaded gasoline in Morocco will not trigger a drastic improvement in air quality, at least in Agadir.  相似文献   
55.
BACKGROUND: After the rinsing of spray equipment, the rinsing water contains polluting products. One way to avoid pollution is to bring the rinsing water over a purification system, a biological bed. The system consists of an impermeable tub filled with a biomix substrate that facilitates biodegradation of pesticides. Usually, straw is one component of the biomix. The objective of this study was to assess the efficiency of an unusual substrate, bagasse, a residue of sugar cane, for the degradation of three pesticides, glyphosate, malathion and lambda‐cyhalothrin. RESULTS: Results showed that more than 99% of malathion and glyphosate were degraded in 6 months. In the biological bed, the DT50 value for malathion was 17 days, for glyphosate 33 days and for lambda‐cyhalothrin 43 days. The degradation rate of aminomethylphosphonic acid (AMPA) residues from the degradation of glyphosate was slower than that of the other pesticides (DT50 69 days). Finally, the innocuousness of the biomix after 6 months of degradation was confirmed by biological tests. CONCLUSIONS: Although the degradation rates of the three pesticides in the present bagasse‐based system were similar to those under temperate conditions, the degradation conditions were improved by comparison with those in soil under the given tropical conditions. Further benefits of this system are pesticide confinement, to avoid their dispersion in the environment by liquids or solids, and a lower overall cost. Finally, possibilities for optimising the bagasse‐based system (e.g. management of the water content and nature of the biomix) are discussed. Copyright © 2008 Society of Chemical Industry  相似文献   
56.
The maintenance of biodiversity in agro-ecosystems is often viewed as an insurance against an uncertain future, yet, there is increasing evidence of biodiversity loss in agricultural landscapes. Here, we examined long term trends in the arable weed flora of North-East France by revisiting 158 arable fields initially surveyed in the 1970s. We assessed changes in species richness, density and frequency of occurrence in weed communities as well as for subgroups that are recognised for their conservation value. We also evaluated the importance of crop edges as potential refugia for the threatened arable weeds. Among the 121 species recorded in both surveys, 40% had significantly declined in frequency while 10% had significantly increased. At the field level, we recorded a 42% decline in species richness and a 67% decline in species density. Trends were comparable for weed species of particular conservation value. In the 2000s survey, crop edges harboured levels of weed diversity that were intermediate between those found in field cores in the 1970s and in the 2000s survey. Our results indicated that many species of conservation value had disappeared or seriously decreased in the field core but still persisted in the crop edge. The consequences of this general decline and possible conservation options are discussed in the light of the results.  相似文献   
57.
BACKGROUND: Since biological degradation processes are known to be a major driver of the natural attenuation of pesticide residues in the environment, microbial communities adapted to pesticide biodegradation are likely to play a key environmental role in reducing pesticide exposure in contaminated ecosystems. The aim of this study was to assess the diuron‐mineralising potential of microbial communities at a small‐scale watershed level, including a diuron‐treated vineyard (pollution source), its associated grass buffer strip (as a river protection area against pesticide runoff) and the lotic receiver hydrosystem (sediments and epilithon), by using radiorespirometry. RESULTS: Comparison of results obtained at different sampling sites (in both soil and aquatic systems) revealed the importance of diuron exposure in the adaptation of microbial communities to rapid diuron mineralisation in the vineyard but also in the contaminated grass strip and in downstream epilithic biofilms and sediments. CONCLUSION: This study provides strong suggestive evidence for high diuron biodegradation potential throughout its course, from the pollution source to the final receiving hydrosystem, and suggests that, after microbial adaptation, grass strips may represent an effective environmental tool for mineralisation and attenuation of intercepted pesticides. Copyright © 2009 Society of Chemical Industry  相似文献   
58.
59.
Chitosan, a partially deacetylated derivative of chitin, was solubilized by bipolar membrane electroacidification (BMEA). Bipolar/monopolar (anionic or cationic) configuration and chitosan addition mode (single step or stepwise) were examined. Chitosan solubility and electroacidification parameters were monitored during the process to determine the optimal conditions. Bipolar/anionic configuration and stepwise feeding mode led to chitosan solubilization yield of 91% in 60 min at 20 mA/cm(2). In this configuration, chitosan solution had a pH of 2.5, a conductivity of 8.5 mS/cm, and an ash content of 0.2%. Relative energy consumption was 0.05 kWh/L of 1% chitosan solution prepared. Although some chitosan particles were aggregated in the electrodialysis stack, limiting chitosan solubilization, BMEA allowed complete solubilization of chitosan circulating in the system.  相似文献   
60.
The intensification of agriculture has led to a loss of biodiversity and subsequently to a decrease in ecosystem services, including regulation of pests by natural enemies. Biological regulation of pests is a complex process affected by both landscape configuration and agricultural practices. Although modeling tools are needed to design innovative integrated pest management strategies that consider tritrophic interactions at the landscape scale, landscape models that consider agricultural practices as levers to enhance biological regulation are lacking. To begin filling this gap, we developed a grid-based lattice model called Mosaic-Pest that simulates the spatio-temporal dynamics of Meligethes aeneus, a major pest of oilseed rape, and its parasitoid, Tersilochus heterocerus through a landscape that changes through time according to agricultural practices. The following agricultural practices were assumed to influence the tritrophic system and were included in the model: crop allocation in time and space, ploughing, and trap crop planting. To test the effect of agricultural practices on biological regulation across landscape configurations, we used a complete factorial design with the variables described below and ran long-term simulations using Mosaic-Pest. The model showed that crop rotation and the use of trap crop greatly affected pollen beetle densities and parasitism rates while ploughing had only a small effect. The use of Mosaic-Pest as a tool to select the combination of agricultural practices that best limit the pest population is discussed.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号