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   90130篇
  免费   4694篇
  国内免费   1582篇
林业   4544篇
农学   3659篇
基础科学   1456篇
  9775篇
综合类   21407篇
农作物   4076篇
水产渔业   3849篇
畜牧兽医   40797篇
园艺   1639篇
植物保护   5204篇
  2022年   876篇
  2021年   1127篇
  2020年   1127篇
  2019年   1132篇
  2018年   1324篇
  2017年   1637篇
  2016年   1391篇
  2015年   1531篇
  2014年   1710篇
  2013年   3510篇
  2012年   2768篇
  2011年   3205篇
  2010年   2405篇
  2009年   2126篇
  2008年   2865篇
  2007年   2779篇
  2006年   2505篇
  2005年   2298篇
  2004年   2026篇
  2003年   2032篇
  2002年   2007篇
  2001年   2533篇
  2000年   2444篇
  1999年   1982篇
  1998年   775篇
  1995年   863篇
  1992年   1521篇
  1991年   1581篇
  1990年   1680篇
  1989年   1667篇
  1988年   1545篇
  1987年   1489篇
  1986年   1537篇
  1985年   1515篇
  1984年   1250篇
  1983年   1144篇
  1979年   1248篇
  1978年   979篇
  1977年   848篇
  1976年   803篇
  1975年   913篇
  1974年   1201篇
  1973年   1240篇
  1972年   1255篇
  1971年   1182篇
  1970年   1102篇
  1969年   1003篇
  1968年   863篇
  1967年   906篇
  1966年   837篇
排序方式: 共有10000条查询结果,搜索用时 875 毫秒
41.
Since the International Society of Veterinary Acupuncture (IVAS) was founded in 1974, acupuncture (AP) has received greater acceptance by veterinary professionals throughout the world. This article introduces some important animal diseases that respond well to AP therapy. These include resuscitation of small animals, treatment of anoestrous gilts and sows, bovine reproductive disease, canine vertebral problems and equine backpain, etc. Conventional medicine considers these to be difficult cases to treat. Veterinarians have become more aware of the benefits of AP especially for those diseases, thanks to the efforts of experienced practitioners and scientists, and the many published reports on veterinary AP that have introduced some good indications for AP therapy in veterinary practice. Possible mechanisms behind the effectiveness of AP are discussed. This article aims to introduce veterinarians to good indications for AP to initiate their interest in the practice of AP. Although this is a rapidly expanding field, a long march must begin with one step. We wish this article to be the shoes for such a march. For more information on veterinary AP, contact IVAS , P.O. Box 1478, Longmont, CO.. 80502, USA (http://www.ivas.org), or your national veterinary acupuncture society (http://www.komvet.at/ ivadkom/vapsocs.htm).  相似文献   
42.
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   
43.
44.
Star catalogues     
  相似文献   
45.
46.
47.
48.
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   
49.
DHA和EPA是ω-3多不饱和脂肪酸,它们俗称脑黄金。世界卫生组织推荐ω-6/ω-3在人体的比例最好在5:1左右。我国居民摄入ω-3普遍不足,所以生产富含ω-3(脑黄金)鸡蛋对社会具有重要意义。本文主要就脑黄金鸡蛋的研究现状和研究中存在的问题作一综述。  相似文献   
50.
Ohne Zusammenfassung  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