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   1145篇
  免费   72篇
林业   94篇
农学   33篇
基础科学   1篇
  248篇
综合类   62篇
农作物   77篇
水产渔业   105篇
畜牧兽医   459篇
园艺   23篇
植物保护   115篇
  2023年   19篇
  2022年   30篇
  2021年   61篇
  2020年   49篇
  2019年   42篇
  2018年   58篇
  2017年   38篇
  2016年   49篇
  2015年   29篇
  2014年   48篇
  2013年   66篇
  2012年   67篇
  2011年   104篇
  2010年   64篇
  2009年   43篇
  2008年   69篇
  2007年   71篇
  2006年   55篇
  2005年   44篇
  2004年   51篇
  2003年   37篇
  2002年   33篇
  2001年   8篇
  2000年   15篇
  1999年   5篇
  1998年   2篇
  1997年   5篇
  1996年   5篇
  1995年   3篇
  1994年   3篇
  1993年   3篇
  1992年   5篇
  1991年   3篇
  1989年   1篇
  1988年   2篇
  1987年   4篇
  1986年   5篇
  1985年   1篇
  1984年   4篇
  1983年   1篇
  1982年   1篇
  1981年   5篇
  1980年   1篇
  1978年   1篇
  1976年   1篇
  1975年   1篇
  1973年   1篇
  1971年   1篇
  1968年   1篇
  1955年   1篇
排序方式: 共有1217条查询结果,搜索用时 31 毫秒
31.
Due to their high biodiversity and adaptation to a mutable and challenging environment, aquatic lophotrochozoan animals are regarded as a virtually unlimited source of bioactive molecules. Among these, lectins, i.e., proteins with remarkable carbohydrate-recognition properties involved in immunity, reproduction, self/nonself recognition and several other biological processes, are particularly attractive targets for biotechnological research. To date, lectin research in the Lophotrochozoa has been restricted to the most widespread phyla, which are the usual targets of comparative immunology studies, such as Mollusca and Annelida. Here we provide the first overview of the repertoire of the secretory lectin-like molecules encoded by the genomes of six target rotifer species: Brachionus calyciflorus, Brachionus plicatilis, Proales similis (class Monogononta), Adineta ricciae, Didymodactylos carnosus and Rotaria sordida (class Bdelloidea). Overall, while rotifer secretory lectins display a high molecular diversity and belong to nine different structural classes, their total number is significantly lower than for other groups of lophotrochozoans, with no evidence of lineage-specific expansion events. Considering the high evolutionary divergence between rotifers and the other major sister phyla, their widespread distribution in aquatic environments and the ease of their collection and rearing in laboratory conditions, these organisms may represent interesting targets for glycobiological studies, which may allow the identification of novel carbohydrate-binding proteins with peculiar biological properties.  相似文献   
32.
33.
The study of anatomy is important to accomplish any kind of surgical and medical procedure and to understand the physiology and diseases of animals. It is no different in veterinary dentistry. The study of oral anatomy helps the veterinarian to accomplish any kind of surgical procedure more quickly and with less damage to tissues, especially in cases of major oral surgery. In fact, under-standing the anatomy is easier when this knowledge is acquired directly, with surgical application. This article describes the essentials of the oral anatomy of the dog and cat, correlating this knowledge with the dental procedures to be used by veterinarians as a guide.  相似文献   
34.
Ungulates are involved in the epidemiology of Borreliosis as maintenance hosts for vector tick species. We evaluated the prevalence of antibodies to Borrelia burgdorferi sensu lato in two different populations of southern chamois in Spain. Forty-six sera (40.4%) were positive at titres >/=1 : 64 using an indirect immunofluorescence assay (IFAT).  相似文献   
35.
A dentigerous cyst was diagnosed in the right rostral maxilla of a 6-month-old Siamese cat affecting the maxillary right canine tooth. The deciduous maxillary right canine tooth was extracted and the dentigerous cyst wall was curetted. The permanent tooth was not removed, however it was mobile following the surgical procedure. Examination 6-months following surgery indicated appropriate development of the tooth with no mobility or periodontal pocket formation. The maxillary right canine tooth had an abnormal shape but was functional with an acceptable appearance.  相似文献   
36.
Background: Hematology and serum biochemistry values can be useful for evaluating the health of populations of captive and free-living European brown hares ( Lepus europaeus ). However, current information is fragmented and incomplete.
Objective: The objective of this study was to determine normal hematology and serum chemistry values for a population of captive European brown hares and to investigate differences related to sex and age.
Methods: Routine hematology and serum chemistry values were determined for 48 captive European brown hares in Catalonia (northeastern Spain): 21 young (6 males and 15 females) and 27 adult (14 males and 13 females) hares. Blood was obtained by auricular venipuncture while animals were physically restrained. Results were expressed as the mean ± SD, and reference intervals were calculated as the mean ± 2SD.
Results: RBC count, PCV, concentrations of hemoglobin, total protein, albumin, gamma globulin, urea nitrogen, and creatinine, and alanine aminotransferase activity were significantly higher in adults than in young hares, and alkaline phosphatase activity and total bilirubin concentration were lower. Sex differences were not observed.
Conclusions: Hematology and serum chemistry results obtained in this study are considered representative for healthy captive European brown hares. A single reference interval can be used for values from male and female hares, however, age-specific intervals are needed for some analytes.  相似文献   
37.
Delayed acute capture myopathy is the term used to describe the clinical syndrome observed in three roe deer captured by drive-nets and transported to an enclosure for scientific purposes. The animals died 48 h, 60 h and 8 days after being captured. The simultaneous deaths coincided with a previous episode of deliberate human disturbance. The histopathological findings were indicative of acute myopathy and myoglobinaemic nephrosis. These could be related to an ataxic myoglobinuric syndrome brought on by capture and transport operations. The lack of clinical signs and negative prognosis indicators in the period between capture and just before death. the absence of gross muscular lesions in the animal that died after 8 days post-capture, the simultaneous deaths of animals captured at different times and the evidence of deliberate human disturbance in the enclosure are suggestive of death triggered by a second stress episode.  相似文献   
38.
Marco I  Domingo M  Lavin S 《Avian diseases》2000,44(1):227-230
One captive male capercaillie (Tetrao urogallus) was found dead on December 1993 at the breeding center of capercaillie in Catalonia, Spain. The bird was emaciated and, at necropsy, had numerous nodules of various sizes subcutaneously in the cervical region, pleura, lungs, liver, spleen, and mesentery. Microscopic examination revealed granulomatous lesions with central caseous necrosis, epithelioid cells, giant cells, and few lymphocytes in all affected organs. Numerous acid-fast bacilli were demonstrated in the tubercles with Ziehl-Nielsen stain.  相似文献   
39.
Abstract: D-dimer is a neoantigen formed when thrombin initiates the transformation of fibrinogen to fibrin; it is derived from plasmin digestion of cross-linked fibrin. In human medicine, the usefulness of this analyte in diagnosing disseminated intravascular coagulation (DIC) has been assessed in patients fulfilling the clinical and laboratory requirements for this disorder. In canine medicine, the use of D-dimer is relatively new. Detailed studies are needed to understand the relationship between D-dimer concentration in plasma and DIC status in dogs. We validated a D-dimer immunoturbidimetric assay (Tina-quant [a] D-Dimer, Boehringer Mannheim) in canine citrated plasma samples. Intra-assay and interassay variability (coefficient of variation) was 5.63% and 8.82%, respectively. The assay was linear, using 2 samples with low and high D-dimer concentrations (r = .996 and .998). Accuracy was 102.2% and 95.7% based on a recovery study in which 2 samples were assessed. Reference values for D-dimer were established using 70 healthy dogs that were assessed clinically and evaluated on the basis of a complete laboratory workup. The reference range was set between 0.02 and 0.28 μg/mL (chi-square test for normal distribution, P > .05).  相似文献   
40.
This study aimed to provide the normal radiographic anatomic appearance of the limbs of the loggerhead sea turtle, Caretta caretta. Dorsopalmar and dorsoplantar radiographs were taken of the forelimbs and hindlimbs of 15 juvenile and 15 subadult loggerhead sea turtles, 17 alive and 13 dead. For comparison, computed tomographic, gross anatomic, osteologic, and histologic studies were performed on the limbs of 5 of the sea turtles. Bones from the distal part of the fore and hind flippers were seen in detail with a mammographic film-screen combination. The pectoral and pelvic girdles, superimposed by the carapace, were better seen on standard radiographs with the use of rare-earth intensifying screens. Mammographic radiographs of the manus of 5 small juvenile turtles showed active growth zones. Visualization of bone contours in the distal part of the limbs was clearer than in mammals owing to the very few superimpositions. The presence of a substantial amount of cartilage in the epiphyses produced better visibility of limb ends. We conclude that use of a mammography film-screen combination is the best way to evaluate the bony and joint structures of the limbs of sea turtles. Radiography provides reliable images for clinical purposes. Considering the low cost and logistics of this technique, it is a practical ancillary test for marine animal rehabilitation centers to use.  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