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   109948篇
  免费   6034篇
  国内免费   72篇
林业   5156篇
农学   3669篇
基础科学   595篇
  13049篇
综合类   15917篇
农作物   3851篇
水产渔业   5488篇
畜牧兽医   60469篇
园艺   1335篇
植物保护   6525篇
  2018年   1646篇
  2017年   1759篇
  2016年   1626篇
  2015年   1442篇
  2014年   1667篇
  2013年   4504篇
  2012年   3146篇
  2011年   3787篇
  2010年   2473篇
  2009年   2375篇
  2008年   3564篇
  2007年   3535篇
  2006年   3319篇
  2005年   3069篇
  2004年   2900篇
  2003年   2976篇
  2002年   2760篇
  2001年   3729篇
  2000年   3607篇
  1999年   2881篇
  1998年   1174篇
  1997年   1129篇
  1996年   1055篇
  1995年   1212篇
  1994年   1094篇
  1993年   1059篇
  1992年   2292篇
  1991年   2538篇
  1990年   2501篇
  1989年   2399篇
  1988年   2214篇
  1987年   2220篇
  1986年   2202篇
  1985年   2154篇
  1984年   1757篇
  1983年   1521篇
  1982年   1019篇
  1979年   1566篇
  1978年   1255篇
  1977年   1104篇
  1976年   1153篇
  1975年   1158篇
  1974年   1419篇
  1973年   1362篇
  1972年   1357篇
  1971年   1253篇
  1970年   1288篇
  1969年   1208篇
  1968年   1055篇
  1967年   1086篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
122.
123.
124.
Colitis cystica profunda in dogs has been diagnosed in one case only. The two own cases were characterized by repeated, partly bloody diarrhea, vomitus, and painful defecation. The disease was diagnosed by clinical examination and colonoscopy with the ensuing histological examination of biopsy specimens. The disease could be managed by administration of a diet, sulfasalazine and corticosteroids.  相似文献   
125.
126.
Echinococcus granulosus worm excretory/secretory antigens (WES) were used in ELISA for diagnosis of E. granulosus infection in dogs and compared with protoscolex somatic antigens (PSM). Sera from 224 dogs were tested. There was no correlation between ELISA absorbance values and E. granulosus worm burdens using either antigen. There was a significant linear relationship between absorbance values of sera tested in the ELISA using WES (W-ELISA) and the ELISA using PSM (P-ELISA). However, there was a small but significant difference between the absorbance values of the sera tested against the two antigens. Western blot analysis of WES using sera from E. granulosus-infected and uninfected dogs revealed antigenic components of relative molecular mass (Mr) larger than 94,000, Mr 94,000-68,000 and Mr 43,000-39,000 in worms, and these were specific for E. granulosus and not identified in PSM; these antigenic differences may be responsible for differences in reactivity in ELISA. The sensitivities of W-ELISA and P-ELISA were 80.8% and 75.6%, respectively. The specificities of W-ELISA and P-ELISA were 93.7% and 97.9%, respectively. The reduced specificity in W-ELISA was mainly attributable to increased background reactivity of sera from Taenia hydatigena-infected dogs. Despite the reduction in specificity, both ELISAs are valuable epidemiological tools to determine the prevalence of antibody to E. granulosus in dog populations and to monitor the success of hydatid control campaigns.  相似文献   
127.
128.
A 2-year-old female Japanese domestic cat weighing 3.6 kg was presented due to marked abdominal distention and was diagnosed as hepatic cyst. The bile acid concentration of the hepatic cyst was as low as the serum bile acid concentration. The membrane of the cysts was excised from the edge of the compressed hepatic tissue and no other surgical manipulation was performed. This surgical procedure is simple and quick compared to hepatic lobectomy, however, it is necessary to evaluate the fluid of the cyst before performing this procedure.  相似文献   
129.
The administration of 20 mg/kg of acetylsalicylic acid in 18 clinically healthy dogs resulted in a thrombocytopathy with lengthened capillary bleeding time and irreversible aggregation inhibition. Through the set up of individual dilution series, one could conclude the proportional percentage of aggregation functional transfused thrombocytes. The capillary bleeding time was shortened after the intravenous injection of prednisolone (5 mg/kg) without measurable influence on the thrombocytes. Compared to the singular use of cortisone or blood transfusion alone, the effect on capillary bleeding time became magnified when one combined transfusion and corticosteroids. The fresh blood conserves (12 hours) were, with respect to the haemostyptical properties, superior to blood stored for 5 days. The component of aggregation-functional thrombocytes was, due to the prophylactic cortisone application prior to transfusion, not increased.  相似文献   
130.
Calicivirus was isolated from the joint of a kitten that had pyrexia, upper respiratory tract disease, and severe shifting-limb lameness. Marked mononuclear inflammation was found in the synovial fluid. Calicivirus infection or live-virus vaccination previously had been associated with arthropathy, but virus had not been recovered from affected joints. Calicivirus infection should be considered as a diagnosis in kittens with fever and arthralgia, especially if there is a history of recent vaccination or upper respiratory tract disease. Lameness associated with calicivirus infection may be severe, but appears to be self-limiting and is associated with an excellent prognosis for recovery.  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