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   136887篇
  免费   7282篇
  国内免费   80篇
林业   6364篇
农学   4317篇
基础科学   785篇
  15502篇
综合类   25435篇
农作物   5345篇
水产渔业   6359篇
畜牧兽医   69772篇
园艺   1615篇
植物保护   8755篇
  2018年   1650篇
  2017年   1807篇
  2016年   1712篇
  2015年   1490篇
  2014年   1828篇
  2013年   4854篇
  2012年   3284篇
  2011年   3953篇
  2010年   2653篇
  2009年   2610篇
  2008年   3971篇
  2007年   3916篇
  2006年   3610篇
  2005年   3457篇
  2004年   3306篇
  2003年   3446篇
  2002年   3190篇
  2001年   4003篇
  2000年   3983篇
  1999年   3246篇
  1998年   1322篇
  1997年   1339篇
  1995年   1515篇
  1994年   1261篇
  1993年   1308篇
  1992年   2712篇
  1991年   2880篇
  1990年   2962篇
  1989年   2949篇
  1988年   2718篇
  1987年   2660篇
  1986年   2769篇
  1985年   2669篇
  1984年   2293篇
  1983年   2023篇
  1982年   1391篇
  1979年   2191篇
  1978年   1707篇
  1977年   1544篇
  1976年   1484篇
  1975年   1613篇
  1974年   2027篇
  1973年   2069篇
  1972年   2072篇
  1971年   1922篇
  1970年   1859篇
  1969年   1752篇
  1968年   1499篇
  1967年   1607篇
  1966年   1404篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Two serological tests (indirect immunofluorescence and enzyme-linked immunosorbent assay) were developed for the detection of fetal antibody to Chlamydia psittaci. Fetal blood and thoracic fluid from 126 field cases of suspected ovine chlamydial abortion were examined using both tests. Placenta and fetal tissues (lung, liver, and kidney) from the same animals were also examined by the following conventional diagnostic methods: isolation in McCoy cells, detection of chlamydial lipopolysaccharide (LPS), modified Ziehl-Nielsen staining, and direct fluorescent antibody staining of chlamydia in frozen cryostat sections. Seventy cases were positive by fetal serology, and of these, 68 were also positive by isolation and/or LPS detection. The remaining 56 cases had negative fetal serology, and of these, 39 were positive by isolation and/or LPS detection. Results indicate that fetal serology, although less sensitive than either isolation in McCoy cells or detection of chlamydial LPS antigen, may be of particular use when placenta is not available.  相似文献   
52.
53.
Star catalogues     
  相似文献   
54.
55.
56.
57.
58.
59.
The feet of three two-humped camels (Camelus bactrianus), one lama (Lama glama) and four alpacas (Lama pacos) from zoos and a circus in the Netherlands were examined for the mange-mite Choroptes bovis. Mites were found on two of the camels, the lama, and three of the alpacas. On one camel and one alpaca small mange lesions on the feet were present. This is the first report of Chorioptes bovis and chorioptic mange in the two-humped camel.  相似文献   
60.
The medical records of 38 horses with puncture wounds of the navicular bursa were reviewed. Only 12 horses had a satisfactory outcome (breeding or riding). Of the remaining 26 horses, 19 were euthanized, five were sold due to persistent severe lameness, one died, and one was lost to long-term follow-up. Different combinations of conservative management prior to surgical debridement and drainage of the navicular bursa were unsuccessful in resolving the condition. Horses that were treated surgically within 1 week of the injury and had a hind leg affected had the best chance of a satisfactory outcome. Additional wound debridement was necessary in 15 horses after initial surgical treatment. The most common complications encountered were navicular bone osteomyelitis and sepsis of the deep digital flexor tendon. Thirteen of 14 horses that had rupture of the deep digital flexor tendon and subluxation of the distal interphalangeal joint had an unsatisfactory outcome. One mare subsequently developed ankylosis of the distal interphalangeal joint and was a useful brood mare. Two horses that had biaxial palmar digital neurectomy because of persistent lameness were later euthanized because of navicular bone fracture and rupture of the deep digital flexor tendon. Results from limited numbers of bacterial cultures and antibiotic sensitivities suggest that penicillin and an aminoglycoside antibiotic should be used as initial antibiotic therapy. Immediate surgical debridement and appropriate antibiotic treatment are recommended as the minimum therapy for penetrating wounds of the navicular bursa in horses.  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