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   152篇
  免费   19篇
林业   1篇
农学   1篇
  15篇
综合类   22篇
农作物   1篇
水产渔业   2篇
畜牧兽医   125篇
植物保护   4篇
  2020年   2篇
  2019年   2篇
  2018年   4篇
  2017年   5篇
  2016年   6篇
  2015年   5篇
  2014年   2篇
  2013年   5篇
  2012年   3篇
  2011年   8篇
  2010年   4篇
  2009年   7篇
  2008年   9篇
  2007年   4篇
  2006年   7篇
  2005年   5篇
  2004年   2篇
  2003年   5篇
  2002年   2篇
  2001年   3篇
  1999年   8篇
  1998年   3篇
  1997年   2篇
  1996年   4篇
  1995年   3篇
  1993年   3篇
  1992年   5篇
  1991年   3篇
  1990年   8篇
  1989年   4篇
  1988年   2篇
  1986年   4篇
  1980年   3篇
  1979年   4篇
  1977年   2篇
  1975年   1篇
  1972年   1篇
  1969年   1篇
  1968年   1篇
  1963年   1篇
  1956年   1篇
  1948年   1篇
  1944年   1篇
  1938年   1篇
  1934年   1篇
  1924年   1篇
  1921年   1篇
  1920年   1篇
  1897年   2篇
  1887年   1篇
排序方式: 共有171条查询结果,搜索用时 15 毫秒
1.
2.
3.
Pigeon circovirus (picv) was detected in cloacal swab samples by means of a newly-developed, sensitive pcr. An initial investigation of 17 Belgian racing pigeons aged up to eight months showed that rates of detection of 88 per cent and above were achieved using samples of cloacal swab, blood and bursa of Fabricius. The sampling of 15 caged pigeons six times when they were from three to 31 weeks of age indicated that picv infections were more readily detected in cloacal swabs than in blood, and that the virus could be detected in cloacal swabs for longer periods after infection than in blood. picv infections were detected in cloacal swabs from 38 of 47 young pigeons aged from two to 31 weeks, from 12 racing lofts, which had clinical signs including diarrhoea and weight loss, regurgitation and respiratory signs. Samples from birds from two infected lofts indicated that picv could be detected in some birds for at least 27 weeks. Although nine of 14 pigeons aged from 32 to 45 weeks were virus-positive, picv was detected in only one of 18 adult pigeons that originated from four infected lofts.  相似文献   
4.
OBJECTIVE: To evaluate outcomes after attenuation of extrahepatic portosystemic shunts in dogs using surgical silk. DESIGN: Retrospective study. PROCEDURE: Case records were reviewed for degree of surgical attenuation, experience of the primary surgeon, perioperative mortality and problems related to persistent portosystemic shunting or shunt ligation. Presence of portosystemic shunting after surgery was evaluated by ammonia tolerance testing, measurement of postprandial serum bile acid, plasma urea and cholesterol concentrations and liver enzyme activity. The influence of age, postocclusion portal pressure, primary surgeon, degree of attenuation and postoperative biochemical findings on the occurrence of postoperative problems was assessed. RESULTS: The mortality rate was 2.1%. Shunt attenuation was complete in 34% and partial in 66% of dogs. Portal hypertension necessitating ligature removal was encountered in only one dog. Five dogs experienced neurological abnormalities (seizures or ataxia), possibly as a manifestation of 'postligation seizure syndrome'. Postoperative liver function was normal in 78% of dogs, including 70% with partial shunt attenuation. Experience of the surgeon was related positively to outcome after partial attenuation (P = 0.002). Postoperative biochemical evidence of abnormal liver function was the most sensitive predictor of recurrence of clinical signs referable to persistent portosystemic shunting. CONCLUSIONS: In the hands of an experienced surgeon, surgical attenuation of single extrahepatic shunts was safe and effective, even in animals with partial attenuation. Most dogs with biochemical evidence of persistent shunting suffer relapse of clinical signs within 18 months of surgery. Postligation neurological syndromes of variable intensity may be more common than previously thought.  相似文献   
5.
6.
Adenoviral infection of the renal interstitium of a lamb   总被引:1,自引:0,他引:1  
  相似文献   
7.
8.
Dose-dependent hypersensitivity responses mounted against antigenic constituents of creep feeds have been previously implicated in intestinal damage, digestive disorders and impaired performance of early weaned pigs. In the present study biochemical and histological investigations of the small intestine were undertaken to determine the putative relationship between creep feed level and hypersensitivity response in pigs weaned at 14 days. Creep feed was administered by gastric intubation and weaned pigs received the same diet by gastric intubation for five days. Mucosal structure and function at weaning were not affected by creep feeding regimen. Villus height decreased and crypt depth increased in weaned compared to suckled pigs, but morphology was unaffected by prior exposure to creep. Xylose absorption was not influenced by either creep feed level or weaning. Intraepithelial lymphocyte numbers increased during weaning but were not affected by the creep feeding regimen. Mucosal carbohydrase activity in weaned pigs was not significantly affected by preweaning treatment. The results do not support the hypothesis that post weaning changes in structure and function of the gut are related to creep feed level or to immune responses to dietary antigens.  相似文献   
9.
10.
SUMMARY A haemodynamically significant ventricular septal defect was diagnosed in a 3-month-old male Cavalier King Charles Spaniel. A median sternotomy was performed and the 6.5 kg dog placed on cardiopulmonary bypass using pump-assisted cross-circulation. A 10 mm diameter peri-membranous ventricular septal defect was closed using a continuous suture of 4–0 polypropylene, via a 2.5 cm incision in the right ventricular outflow tract. The duration of cardiopulmonary bypass was 90 minutes. Complications in the immediate postoperative period were mild and easily managed.  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