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   199篇
  免费   55篇
林业   4篇
农学   1篇
  10篇
综合类   13篇
农作物   4篇
水产渔业   4篇
畜牧兽医   202篇
园艺   2篇
植物保护   14篇
  2023年   2篇
  2022年   2篇
  2021年   4篇
  2020年   2篇
  2019年   5篇
  2018年   4篇
  2017年   5篇
  2016年   7篇
  2015年   5篇
  2014年   2篇
  2013年   10篇
  2012年   5篇
  2011年   5篇
  2010年   2篇
  2009年   3篇
  2008年   10篇
  2007年   9篇
  2006年   8篇
  2005年   14篇
  2004年   7篇
  2003年   13篇
  2002年   10篇
  2001年   13篇
  2000年   12篇
  1999年   12篇
  1998年   7篇
  1997年   2篇
  1996年   2篇
  1993年   5篇
  1992年   4篇
  1991年   7篇
  1990年   8篇
  1989年   9篇
  1988年   6篇
  1986年   2篇
  1984年   2篇
  1983年   4篇
  1981年   2篇
  1980年   1篇
  1979年   1篇
  1978年   2篇
  1976年   2篇
  1974年   1篇
  1972年   3篇
  1971年   1篇
  1970年   2篇
  1969年   3篇
  1967年   2篇
  1941年   1篇
  1906年   1篇
排序方式: 共有254条查询结果,搜索用时 15 毫秒
21.
22.
23.
Six healthy horses were anaesthetised with halothane (1·2 times the horse minimal alveolar concentration) in oxygen for more than 12 hours. Serum bilirubin, aspartate aminotransferase, alkaline phosphatase and L-iditol dehydrogenase values were significantly (P<0·05) increased for up to nine days after anaesthesia. These changes suggest au anaesthesia related liver dysfunction. Creatine kinase increased to an average of more than 1400 iu litre−1 24 hours after anaesthesia and this change is indicative of muscle cell disruption. Renal-associated biochemical results, (that is serum creatinine and inorganic phosphate concentrations) were significantly increased transiently and are indicative of reduced renal function during and immediately after anaesthesia. Plasma concentrations of eicosanoids (6-keto-PGF1a, PGF2a, pge and thromboxane) following anaesthesia were not different from preanaesthetic values. The magnitude of liver and muscle cell related increases in serum enzyme activities resulting from prolonged halothane anaesthesia was in excess of that previously reported for anaesthesia of shorter duration.  相似文献   
24.
25.
Searching the world wide Web   总被引:8,自引:0,他引:8  
The coverage and recency of the major World Wide Web search engines was analyzed, yielding some surprising results. The coverage of any one engine is significantly limited: No single engine indexes more than about one-third of the "indexable Web," the coverage of the six engines investigated varies by an order of magnitude, and combining the results of the six engines yields about 3.5 times as many documents on average as compared with the results from only one engine. Analysis of the overlap between pairs of engines gives an estimated lower bound on the size of the indexable Web of 320 million pages.  相似文献   
26.
Colonic adenocarcinoma with osseous metaplasia in a horse   总被引:1,自引:0,他引:1  
Rectal palpation of a 30-year-old mixed-breed mare with chronic weight loss and intermittent, refractory abdominal pain revealed a mass in the right caudoventral portion of the abdomen. Hematologic and serum biochemical findings were normal except for slight mature neutrophilia and mildly high alkaline phosphatase activity and total bilirubin concentration. Cytologic examination of a specimen obtained by abdominocentesis revealed equal numbers of nondegenerative neutrophils and macrophages, but no evidence of neoplastic cells. The mare continued to have signs of abdominal discomfort and was euthanatized. Necropsy revealed a large mass at the junction of the right dorsal colon and transverse colon, and several smaller masses in the liver. Histologic characteristics of the small-colon mass were consistent with colonic adenocarcinoma with osseous metaplasia.  相似文献   
27.
SUMMARY To determine whether oral cobalt supplements could modify the clinical onset of annual ryegrass toxicity, groups (n = 5) of sheep were dosed orally with 0, 4 or 16 mg cobalt/day. After 3 weeks on this treatment, toxic ryegrass seed was added to their feed to provide 0, 0.15 and 0.30 mg corynetoxins/kg body weight, daily. Sheep receiving cobalt ingested 30% more toxin than did unsupplemented sheep before clinical signs developed (P = 0.03). There was no significant difference between groups receiving 4 and 16 mg cobalt. The results showed that cobalt delayed, but did not prevent, the onset of clinical signs of annual ryegrass toxicity.  相似文献   
28.
An inactivated Salmonella hadar vaccine was administered to parent turkey stock and the progeny were subjected to challenge with S hadar. There was some evidence that eggs from vaccinated birds were more resistant to growth of the organism. When compared with similarly infected poults from unvaccinated parents, a markedly different serological picture and pattern of salmonella excretion was seen. It appeared that the passive immunity induced by the vaccine encouraged the faster establishment of other gut Enterobacteriacae, even in the presence of large numbers of S hadar.  相似文献   
29.
Six animals were used to compare simple interrupted, simple continuous, and stapled techniques for end-to-end rotated small colon anastomoses. Three ponies were evaluated three days after surgery for adhesion formation and luminal diameter at each anastomosis site. Two ponies and one horse were evaluated 14 days after surgery for adhesion formation. All anastomosis sites were examined histologically for alignment of tissue planes, and evidence of inflammation. No single technique was superior in all areas examined. While only three of the nine anastomoses had mild fibrinous adhesions at three days after surgery, all anastomoses had varying degrees of well-organized adhesions by 14 days after surgery. Three days after surgery luminal diameter was most comprised by the simple continuous technique. Although the simple interrupted technique was most consistent in its alignment of tissue planes, it was only slightly better than the simple continuous pattern. Stapled anastomoses were inverted or everted at all sites examined. Adhesion formation was less extensive, and histologic evidence of inflammation was less severe, in stapled anastomoses. The average times required to complete the simple interrupted, simple continuous, and stapled anastomoses were 22, 14, and 8 minutes, respectively.  相似文献   
30.
Cyclopiazonic acid dissolved in corn oil was administered by gavage to broiler chicks (n = 80) daily, from the day of hatching for 23 days. Chicks were assigned to 3 groups (1, 2, or 4 mg of cyclopiazonic acid/kg of body weight); a control group was given corn oil. Each group was composed of 10 male and 10 female chicks. Surviving chicks were euthanatized and necropsied on day 24. Histologic examination revealed that the most common lesions consisted of necrosis and hemorrhage or hyperplasia of the mucosa of the proventriculus and hepatocellular vacuolation. Skeletal muscle degeneration, characterized by myofiber swelling or fragmentation accompanied by an infiltrate of macrophages and heterophils, was detected in the group given 4 mg/kg. This degeneration was associated with an increase of plasma creatine kinase activity. Focal hepatocellular and splenic necrosis also developed in the groups given 4 mg/kg.  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