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   177篇
  免费   54篇
林业   2篇
基础科学   1篇
综合类   23篇
农作物   3篇
水产渔业   6篇
畜牧兽医   192篇
园艺   2篇
植物保护   2篇
  2020年   5篇
  2019年   6篇
  2018年   4篇
  2017年   4篇
  2016年   7篇
  2015年   8篇
  2014年   7篇
  2013年   10篇
  2012年   7篇
  2011年   3篇
  2010年   5篇
  2009年   12篇
  2008年   4篇
  2007年   3篇
  2006年   9篇
  2005年   7篇
  2004年   7篇
  2003年   4篇
  2002年   2篇
  2001年   5篇
  2000年   4篇
  1999年   7篇
  1998年   9篇
  1997年   7篇
  1996年   7篇
  1995年   2篇
  1994年   4篇
  1993年   3篇
  1992年   5篇
  1991年   3篇
  1990年   8篇
  1989年   6篇
  1988年   1篇
  1987年   7篇
  1986年   8篇
  1985年   4篇
  1984年   4篇
  1983年   3篇
  1982年   2篇
  1981年   1篇
  1979年   1篇
  1978年   2篇
  1977年   2篇
  1975年   1篇
  1974年   2篇
  1972年   1篇
  1971年   4篇
  1970年   2篇
  1967年   1篇
  1931年   1篇
排序方式: 共有231条查询结果,搜索用时 15 毫秒
101.
102.
Thirty-six diarrheic calves infected with rota- and coronaviruses were randomly allocated to one of three oral electrolyte treatments: Ion-Aid (Syntex Agribusiness), Life-Guard (Norden Inc), or Revibe (Langford Inc). The calves were also allowed voluntary access to milk which was offered at the rate of 5% of body weight per feeding in two feedings daily. There were significant differences in recovery rate among calves treated with the different electrolytes. Only 33% of Ion-Aid-treated calves recovered; Revibe- and Life-Guard-treated calves had high recovery rates of 92% and 83%, respectively. The much higher recovery rates with Life-Guard and Revibe were attributed to the presence of an alkalizing agent in these preparations. Life-Guard uses bicarbonate to counteract acidosis and there was some evidence that this may have interfered with milk digestion. Revibe uses acetate; this was effectively metabolized within the calves' tissues and produced alkalization without interference with milk digestion.  相似文献   
103.
Summary The reasons for making this study, to determine the haematology and histopathology of an infection caused by one species of trypanosome in one species of animal in the absence of intercurrent disease and other complicating factors, have been detailed. A histopathological examination suggested the presence of a chronic low-grade toxaemia and an anaemic hypoxia.
Résumé Les raisons d'entreprendre cette étude, déterminer l'hématologie et l'histopathologie d'une infection causée par une certaine espèce de trypanosome sur un animal spécifique en l'absence d'autres maladies et complications, ont été détaillées. Un examen histopathologique suggéra la présence d'une toxémie chronique peu importante et d'une anémie hypoxique.
  相似文献   
104.
An indoor, 2-year-old, spayed female domestic cat was referred to the University of Missouri Veterinary Medical Teaching Hospital (UMC-VMTH) for evaluation of weight loss and polyphagia of 1-year duration, with recent episodes of generalized weakness and lethargy. These episodes occurred approximately once per month over the past 4 months. The cat produced frequent stools, which were occasionally poorly formed. A CBC and serum biochemistry were performed 1 and 5 months before referral, and leukopenia (1,200/μL; reference interval, 3,500-16,000/μL; no differential provided), hypocholesterolemia (64 mg/dL and 46 mg/dL; reference interval, 75–220 mg/ dL), and hypotriglyceridemia (22 mg/dL and 16 mg/dL; reference interval, 26–160 mg/dL) were identified. The most recent serum biochemistry results disclosed mild hypercalcemia (11.3 mg/dL; reference interval, 8.2–10.8 mg/ dL) and hypernatremia (163 mg/dL; reference interval, 145–158 mg/dL). Antibody titers for Toxoplasma were consistent with past exposure (immunoglobulin M [IgM] negative; IgG 1:256).  相似文献   
105.
Information for veterinarians regarding diseases of farmed elk remains scarce despite an increase in the size of the industry. This retrospective study examines all (n=245) elk cases admitted to the Western College of Veterinary Medicine over an 11-year period (1991 to 2001). Age, gender, date of admission, diagnosis, and outcome were examined. Diarrhea, fractures, and other musculoskeletal problems were most common. Most (76%) cases involved elk under 1 y of age; these were more commonly diagnosed with fractures or diarrheal disease. Elk older than 1 y of age tended to be diagnosed with fractures or noninfectious diseases. Overall, the most common diagnosis was fractures, which were seen mostly as traumatic catastrophic long bone fractures. Fractures and other musculoskeletal problems occurred towards the end of summer and into the fall, while diarrhea and other infectious diseases were diagnosed in young elk in the spring and summer. The in-hospital case fatality rate was 33.5%.  相似文献   
106.
107.
AIM: To determine the half life (T1/2), time taken to reach maximum plasma concentration (Tmax) and maximum plasma concentration (Cmax) of thalidomide in sheep following I/V, oral and topical treatment with a single dose of thalidomide.

METHOD: Three groups of 4–6-month-old ram lambs were treated with thalidomide dissolved in dimethylsulphoxide (DMSO). The first group (n=10) was treated I/V with 100?mg thalidomide in 2?mL DMSO; the second group (n=8) received 400?mg thalidomide in 2?mL DMSO orally, and the third group (n=8) had 400?mg thalidomide in 4?mL DMSO applied topically. Plasma samples were collected up to 36 hours after treatment, snap-frozen at ?80°C and analysed for concentrations of thalidomide using high performance liquid chromatography.

RESULTS: Following I/V administration, T1/2 was 5.0 (SEM 0.4) hours, volume of distribution was 3,372.0 (SEM 244.3) mL/kg and clearance was 487.1 (SEM 46.1) mL/hour.kg. Topical application of 400?mg thalidomide did not increase plasma concentrations. Following oral administration, thalidomide bioavailability was 89%, with T1/2, Tmax, and Cmax being 7.2 (SEM 0.8) hours, 3.0 (SEM 0.4) hours and 1,767.3 (SEM 178.1) ng/mL, respectively.

CONCLUSION: Topical administration using DMSO as a solvent did not increase concentrations of thalidomide in plasma. The mean pharmacokinetic parameters determined following oral treatment with 400?mg of thalidomide were similar to those reported in humans receiving a single 400?mg oral dose (T1/2 7.3 hours; Tmax 4.3 hours and Cmax 2,820?ng/mL). There is potential for thalidomide to be used as a model for the treatment of chronic inflammatory conditions in sheep, such as Johne's disease, where tumour necrosis factor alpha plays a pathogenic role.  相似文献   
108.
109.
REASONS FOR PERFORMING STUDY: The reliability of diagnoses of obstructive conditions of the upper respiratory tract (URT) based on examinations performed at rest vs. at exercise is controversial. OBJECTIVE: To compare diagnosis of URT by endoscopy at rest with that achieved during high-speed treadmill exercise (HSTE). HYPOTHESIS: Endoscopy of URT at rest, when performed in isolation from other simpler techniques is unreliable in the prediction of dynamic respiratory obstructions. METHODS: Endoscopic findings of 600 Thoroughbred racehorses during quiet breathing were compared with findings during high-speed treadmill exercise. Other parameters were also assessed for their specificity in diagnosis. RESULTS: Endoscopy of the resting horse showed low sensitivity (0.15) in the diagnosis of dorsal displacement of the soft palate (DDSP) and palatal instability (PI). When endoscopy and reported noises were taken together there was still a 35% misdiagnosis rate. Although there was significant association between resting laryngeal function score (LFS) and dynamic vocal cord and/or arytenoid cartilage collapse at exercise, 19% of horses with a grade 4/5 LFS were able to attain and maintain full abduction during exercise and 7% of those with 'normal' grades 1 or 2 LFS at rest showed dynamic laryngeal collapse when exerted. Sensitivity of the diagnostic model was greatly increased (80%) when a history of inspiratory noise and palpable intrinsic muscle atrophy were included. CONCLUSIONS AND POTENTIAL RELEVANCE: Endoscopy of the upper respiratory tract of static horses is unreliable in the diagnosis of dynamic obstructions of the URT and should not be used in isolation in surgical decision-making or in the assessment of horses at the time of sale.  相似文献   
110.
OBJECTIVE: To evaluate the effectiveness of a self-learning computer module (SLCM) versus traditional instruction in teaching how to pass a nasogastric tube (NG) in the horse. DESIGN: A double-blind, monocentric study. SAMPLE POPULATION: 52 third-year students in the DVM program were randomly assigned to two groups: traditional instruction (N = 25) or SLCM instruction (N = 27). PROCEDURE: Traditional instruction consisted of an instructor and live demonstration; SCLM students were given a CD-ROM each. Both sessions lasted one hour. The students were then united in one session to practice passing the NG tube. Their performance was videotaped and evaluated by two evaluators. Students were then given a multiple-choice knowledge quiz. One week later, a second demonstration of the same procedure by the two methods was administered, and students were allowed to choose either method of instruction. A Likert-scale questionnaire about their comfort, their confidence, and the appropriateness of the teaching method was given after the second demonstration. Data were analyzed by non-parametric tests. A focus-group study was conducted to determine students' perception of each teaching method. Nine participants in the experiment volunteered for these focus-group sessions. The sessions were audiotaped and transcribed. RESULTS: Students in the SLCM group performed significantly better on the test of knowledge than traditionally instructed students. The questionnaire found significant perceived benefits to computer-based instruction, including a preference for the computer-based module, better learning, and greater preparedness. In hands-on skill, time to pass the NG tube on the successful attempt was significantly shorter in the SLCM group than in the traditionally instructed group. The data from focus-group sessions suggest that while participants expressed satisfaction with both modes of instruction, the SLCM group reported somewhat higher levels of confidence in their skills prior to performing the procedure. Whereas the traditional group reported a strong preference for continued live demonstrations of the procedure, the SLCM group stated that the computer-assisted module alone provided them with effective instruction. CONCLUSION: Computer-assisted learning is an acceptable and effective method of training students to pass an NG tube with potential welfare, proficiency, and knowledge advantages.  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