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   91篇
  免费   21篇
林业   6篇
农学   2篇
  11篇
综合类   8篇
农作物   3篇
水产渔业   2篇
畜牧兽医   78篇
园艺   2篇
  2023年   3篇
  2021年   1篇
  2020年   4篇
  2019年   2篇
  2018年   5篇
  2017年   3篇
  2016年   8篇
  2015年   6篇
  2014年   5篇
  2013年   9篇
  2011年   8篇
  2010年   1篇
  2009年   6篇
  2008年   5篇
  2007年   3篇
  2006年   5篇
  2003年   2篇
  2002年   2篇
  2000年   4篇
  1999年   2篇
  1998年   2篇
  1997年   1篇
  1996年   2篇
  1993年   1篇
  1992年   3篇
  1991年   3篇
  1990年   5篇
  1989年   2篇
  1977年   1篇
  1976年   1篇
  1973年   2篇
  1971年   2篇
  1967年   1篇
  1947年   1篇
  1929年   1篇
排序方式: 共有112条查询结果,搜索用时 390 毫秒
71.
Leptospirosis is a zoonosis, found worldwide, affecting many species of animals. We conducted a cross-sectional study to estimate the prevalence of Leptospira borgpetersenii sv Hardjo and Leptospira interrogans sv Pomona in cattle in dairy herds in South-Western Victoria, Australia. Fifty-three herds were enrolled in the study. Urine samples were collected from 15 late-lactation cows in each herd. A questionnaire was provided to herd managers at the time of each herd visit, asking them to describe the methods they used for controlling leptospirosis, including vaccination. Urine samples were pooled at the herd level and tested for leptospira spp. using real time PCR. Urine samples from individual cows within the positive pooled samples were then tested for Leptospira Hardjo and Leptospira Pomona using qPCR. Four of the 53 herds showed positive leptospirosis results giving an apparent prevalence of 8 (95% CI 2–18) leptospira-positive herds per 100 herds at risk. Based on the 53 completed questionnaires, leptospirosis vaccination programs were not compliant with label directions in 36 of the 52 vaccinated herds: 69 (95% CI 55–81) of 100 herd managers that routinely vaccinated for leptospirosis did not comply with label directions. One herd was completely unvaccinated. Based on our findings, we estimate that approximately 10% of dairy farms in South-Western Victoria are likely to be infected with leptospirosis. While most herds are vaccinating for leptospirosis, most are not doing so according to label directions. We conclude that herd managers need to be better educated regarding leptospirosis vaccination programs.  相似文献   
72.
Single-agent intramedullary cisplatin chemotherapy provided effective localised control in two of four dogs with advanced stage osteosarcoma unable to withstand an amputation or limb-sparing surgery. Complete remission of the local neoplasm was observed in one of the four dogs, partial remission of the local neoplasm in one dog and progressive disease in the other two. Limb function was preserved in one dog for seven months and that dog was found to be tumour-free when euthanased due to unrelated causes. These preliminary results warrant further investigation into the use of intramedullary cisplatin chemotherapy in the localised management of canine appendicular osteosarcoma. It is possible that this mode of treatment may be combined with other treatments to maximise the survival (ie, systemic control) in other dogs affected with appendicular osteosarcoma.  相似文献   
73.
74.
Ephemeral fever remains a viral disease of considerable importance to many countries including Australia. The virus has been only partly characterised and still awaits final classification. Although BEF virus was first thought to contain 6 structural proteins there is increasing evidence to suggest that it contains the 5 proteins characteristic of the Rhabdoviridae. Although BEF is thought to be arthropod borne, the vector has yet to be identified but it is clear from the distribution of BEF that more than one vector is capable of transmitting the disease. Despite rigorous investigation of the clinical signs and the pathology of ephemeral fever, little progress has been made on the pathogenesis of the disease. This has been partly due to the difficulty of propagating BEF virus in vitro and the inability to define the site of replication. However, there is mounting evidence to suggest that BEF is immunopathologic in nature and that the clinical expression of the disease is influenced by the release of one or more mediators of inflammation. The disease is characterised by a number of haematological and biochemical changes and early and prolonged treatment with phenylbutazone is capable of reversing a number of these changes. The intravenous administration of calcium can now be considered a justifiable addition to the treatment regimen together with prolonged phenylbutazone therapy. The vaccines currently available are prepared from either live attenuated or killed virus and may be less than reliable. There appears to be a need for a reliable, inexpensive, cold-chain independent alternative vaccine.  相似文献   
75.
eryl C.  Jones  DVM  PhD  Donald C.  Sorjonen  DVM  MS  Stephen T.  Simpson  DVM  MS  Joan R.  Coates  DVM  MS  Stephen D.  Lenz  DVM  PhD  John T.  Hathcock  DVM  MS  Michelle W.  Agee  MD  PhD  Jan E.  Bartels  DVM  MS 《Veterinary radiology & ultrasound》1996,37(4):247-256
In a three-year prospective study, computed tomographic (CT) and surgical findings were compared for nine large breed dogs with lumbosacral stenosis. Surgically-excised tissue was examined histologically in seven dogs and additional necropsy evaluation was performed in one dog. The CT abnormalities observed at sites of confirmed cauda equina compression were: loss of epidural fat, increased soft tissue opacity, bulging of the intervertebral disc margin, spondylosis, thecal sac displacement, narrowed intervertebral foramen, narrowed vertebral canal, thickened articular process, articular process subluxation, articular process osteophyte, and telescoped sacral lamina. The CT characteristics of lumbosacral degenerative disease and discospondylitis were similar to those described in humans. In three dogs, CT findings at the site of cauda equina compression were consistent with congenital or developmental spinal stenosis, but the method of surgical exposure precluded confirmation. Epidural fibrosis (eight dogs) and multi-level CT abnormalities (six dogs) were identified but the cause(s) and significance were unknown.  相似文献   
76.
The juçara fruits (Euterpe edulis Martius), native to the Atlantic Forest, are rich in anthocyanins. To preserve the anthocyanins in juçara fruit pulp, this study aimed to evaluate the effectiveness of microencapsulation by spray drying and freeze drying with maltodextrin (dextrose equivalent 16.5 to 19.5) and gum arabic in different proportions. The obtained microparticles were characterized by quantifying the total polyphenol and anthocyanin contents, by performing differential scanning calorimetry, thermogravimetry, and infrared spectroscopy and by using scanning electron microscopy to analyze the morphology of the particles. The total amount of polyphenols in the fruit pulp was 750?±?16.7 mg GAE/100 g of the freeze-dried sample. The total anthocyanins in the fruit pulp was 181.25?±?5.36 (mg/100 g). The microparticles were formed by employing maltodextrin and gum arabic in a 1:1 proportion as the polymeric matrix; the mixtures of pulp and polymeric matrix were prepared in proportions of 2:3 and 2:1, preserving up to 83.69% of the anthocyanin content. Lyophilization of the 2:1 mixture resulted in an anthocyanin content of 116.89?±?4.43 (mg/100 g), whereas lyophilization of the 2:3 mixture resulted in 151.68?±?1.39 (mg/100 g) anthocyanin content, which did not differ from the value obtained by spray drying the 2:3 mixture (150.76?±?5.79 (mg/100 g)). Thermal analyses showed that the microparticles obtained by freeze drying at a ratio of 2:3 presented greater resistance to degradation with increasing temperature. The incorporation of the pulp in the polymeric matrix was demonstrated by IR analyses. Microparticles obtained by freeze drying showed the formation of various-sized flakes, whereas those obtained by spray drying were spherical in shape. Microencapsulation is a possible alternative for improving the stability of the anthocyanins in this fruit.  相似文献   
77.
OBJECTIVE: To develop a safe neurosurgical procedure that accessed the ventral pons and medulla of the dog primarily for the removal of brain stem neoplasms. STUDY DESIGN: In vivo study. METHODS: A cadaver study was performed on mesocephalic dog heads to develop a neurosurgical approach to the ventral brain stem. Based on this study, an approach to the ventral brain stem was developed by basioccipital craniectomy. This procedure was performed on 4 young neurologically normal Beagle dogs to assess morbidity and mortality associated with the procedure. Morbidity was evaluated by subjective criteria, daily complete neurologic examinations, comparison of preoperative and postoperative brain stem auditory evoked response (BAER) tests, and postmortem examinations. RESULTS: Three dogs developed a transient cough but were neurologically normal after surgery. One dog was euthanatized within 12 hours of surgery because of severe postoperative morbidity associated with basilar artery disruption due to improper development of the craniectomy. Prolongations of postoperative BAER latencies were observed in 2 dogs but did not appear to be associated with clinical deficits or histopathologic changes in the brain stem. Minimal histopathologic changes were observed except in the dog with basilar artery disruption. Results of this study indicate that, although technically challenging, this procedure can be performed with minimal morbidity. CLINICAL IMPLICATIONS: The main indication for this procedure is surgical reduction or biopsy of ventrally located brain stem neoplasms in dogs. The major disadvantage is anatomic restrictions that prevent access to laterally oriented ventral brain stem masses.  相似文献   
78.
79.
Summary The effects of N on quality and storage life of oranges were investigated in a factorial field experiment at Griffith N.S.W., Australia. The trees that did not receive any ammonium sulphate (N0) produced fruit with the best quality of juice. However, such trees had only one quarter of the total yield (by weight) of trees receiving 2 kg ammonium sulphate (N1) per annum. Higher levels of ammonium sulphate (4 and 8 kg; N2 and N4 respectively) did not increase in yield or quality as judged by the total soluble solids (T.S.S.) to titratable acid ratio of the juice. N1 — trees had produced more juice and total soluble solids than other treatments. Organoleptic tests favoured juice with the highest T.S.S./acid ratio and the lowest percentage titratable acid. Although fruit stored at 0°C had the least fungal wastage, that stored at 15°C had less rind breakdown and total wastage (fungal + rind breakdown). Low temperature rind breakdown was particularly evident at 7.5°C and most oranges were affected irrespective of nitrogen treatment. At 20°C and 25°C, a high temperature rind breakdown was found with N4 — fruit on short storage, and in other fruit after longer storage. Associated with the rind breakdown and preceding its appearance was a higher rate of respiration. Some typicalSeptoria spot (with pycnidia) was found at 20°C and the high temperature rind breakdown is possibly related to this disease or its due to another pathogen; it was not possible to decide definitely its origin, whether pathogenic or physiological. In general N0 — and N1 —fruits stored better at most temperatures than N2 — and N4 — fruits. Respiration rate at 20°C was similar irrespective of treatment; a climacteric rise in evolution of carbon dioxide was not found. Yield, internal quality and storage life of fruit, considered collectively, indicated that trees receiving 2 kg sulphate of ammonia per tree per annum were, superior to all other treatments in this experiment.  相似文献   
80.
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