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   17036篇
  免费   898篇
  国内免费   17篇
林业   828篇
农学   558篇
基础科学   122篇
  2505篇
综合类   2664篇
农作物   911篇
水产渔业   950篇
畜牧兽医   8308篇
园艺   197篇
植物保护   908篇
  2020年   161篇
  2019年   182篇
  2018年   310篇
  2017年   365篇
  2016年   261篇
  2015年   198篇
  2014年   316篇
  2013年   665篇
  2012年   496篇
  2011年   620篇
  2010年   428篇
  2009年   410篇
  2008年   628篇
  2007年   552篇
  2006年   513篇
  2005年   453篇
  2004年   420篇
  2003年   429篇
  2002年   369篇
  2001年   486篇
  2000年   475篇
  1999年   373篇
  1998年   180篇
  1997年   201篇
  1996年   156篇
  1995年   192篇
  1993年   164篇
  1992年   280篇
  1991年   313篇
  1990年   307篇
  1989年   312篇
  1988年   289篇
  1987年   246篇
  1986年   295篇
  1985年   253篇
  1984年   209篇
  1983年   207篇
  1979年   250篇
  1978年   165篇
  1977年   155篇
  1975年   171篇
  1974年   234篇
  1973年   215篇
  1972年   251篇
  1971年   230篇
  1970年   203篇
  1969年   192篇
  1968年   158篇
  1967年   160篇
  1966年   161篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
A haematological disorder in a dog characterised by a massive leucocytosis, mainly composed of eosinophils and their precursors is reported here. The normal composition of cells in the bone marrow was displaced in favour of the eosinophils and their precursors. No apparent cause for the pronounced eosinophilia could be determined by clinical, haematological, clinical-chemical, radiological or pathological examinations. A diagnosis of eosinophilic leukaemoid reaction was suggested as the criteria for the diagnosis of eosinophilic leukaemia in the dog but this was not firmly established.  相似文献   
92.
93.
94.
95.
96.
Medetomidine (200 μg/kg) was administered orally and, on a seperate occasion, im to 7 cats. Peak serum drug concentrations were reached more slowly after oral (43.6 ± 14.3 min) than after im administration (21.6 ± 10.0 min). The onset of sedation and recumbency lagged after oral administration. There were no statistically significant differences between the 2 routes of administration in peak serum concentrations, systemic drug availability or extent of sedation. However, there was considerable variation in these parameters between individuals after oral administration. The extent of salivation correlated negatively with systemic drug availability after oral administration. Where excessive salivation did not occur, systemic drug availability and the depth of sedation were comparable to, or even higher than, were obtained after the corresponding im administrations. In conclusion, oral administration of medetomidine induced a clinical sedation but, when accurate dosing is a necessity, the oral route may not be very reliable due to possible drug losses through salivation.  相似文献   
97.
98.
Bovine leukocyte adhesion deficiency (BLAD) was identified in a two-month-old Holstein heifer calf using DNA-polymerase chain reaction analysis of the affected calf and other clinical parameters. Neutrophil integrin expression (CD18, CD11a, CD11c), aggregation, and transendothelial migration were studied in vitro. Neutrophils were isolated from the affected calf and from normal, healthy, age-matched control Holstein calves. Neutrophils isolated from the affected BLAD calf had decreased expression of leukocyte integrins on their cell surface, decreased ability to aggregate in response to chemotactic stimuli, and decreased ability to migrate across bovine endothelial cell monolayers in vitro. Transendothelial migration of neutrophils from normal calves was reduced to levels comparable to the BLAD neutrophils by treatment with an anti-CD18 monoclonal antibody (MAb 60.3). Peripheral-blood lymphocytes from the BLAD calf also expressed negligible levels of leukocyte integrins, similar to their neutrophil counterparts. Our experimental findings in vitro correlate well with the clinical observations of decreased leukocyte trafficking and diminished host defense in leukocyte adhesion-deficient animals. The syndrome of BLAD may be a suitable model for one of the human leukocyte adhesion deficiency disorders.  相似文献   
99.
100.
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