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   877篇
  免费   81篇
  国内免费   2篇
林业   55篇
农学   19篇
基础科学   3篇
  148篇
综合类   105篇
农作物   28篇
水产渔业   68篇
畜牧兽医   447篇
园艺   24篇
植物保护   63篇
  2024年   2篇
  2023年   10篇
  2022年   17篇
  2021年   25篇
  2020年   23篇
  2019年   23篇
  2018年   20篇
  2017年   33篇
  2016年   29篇
  2015年   36篇
  2014年   36篇
  2013年   34篇
  2012年   55篇
  2011年   67篇
  2010年   51篇
  2009年   51篇
  2008年   68篇
  2007年   63篇
  2006年   54篇
  2005年   37篇
  2004年   53篇
  2003年   45篇
  2002年   40篇
  2001年   15篇
  2000年   6篇
  1999年   5篇
  1998年   5篇
  1997年   2篇
  1996年   5篇
  1995年   4篇
  1994年   5篇
  1993年   3篇
  1992年   4篇
  1991年   3篇
  1989年   4篇
  1987年   2篇
  1985年   1篇
  1983年   3篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1978年   1篇
  1977年   1篇
  1976年   2篇
  1972年   2篇
  1970年   2篇
  1969年   1篇
  1968年   3篇
  1941年   1篇
  1932年   1篇
排序方式: 共有960条查询结果,搜索用时 0 毫秒
61.
Fiez  Tim 《Precision Agriculture》2002,3(4):353-358
In response to rapidly growing interest in precision farming, universities and others have developed numerous educational programs. Many of these events are multi-day conferences and workshops as these venues provide the time necessary for attendees to learn about the many technologies, analysis approaches, and management strategies that make up precision farming. The Washington State University Western Precision Agriculture Conference, the Assiniboine Community College Precision Agriculture Conference and the University of Nebraska–Lincoln Crop Modeling for Environment-Specific Management Workshop exemplify these types of educational programs. The Western Precision Agriculture Conference uses a traditional format where the audience primarily listens to presentations. The Assiniboine Community College Precision Agriculture Conference provides a mixture of presentations and hands-on sessions where attendees actually use precision farming tools or develop site-specific management plans. Finally, those who attend the University of Nebraska–Lincoln Crop Modeling for Environment-Specific Management Workshop complete exercises related to each topic and presentation. Because a conference or workshop brings many experts together for a short period of time, organizers of all three events have tried to capture conference content for later use in other educational programs. Their approaches to this include videotaping interviews of conference speakers and assembling software and data used during the conference on compact disk. Given the multidisciplinary nature of precision farming, conferences and workshops that utilize multiple expert presenters such as those discussed in this paper are among the best sources of precision farming education.  相似文献   
62.
63.
Domesticated nature: shaping landscapes and ecosystems for human welfare   总被引:2,自引:0,他引:2  
Like all species, humans have exercised their impulse to perpetuate and propagate themselves. In doing so, we have domesticated landscapes and ecosystems in ways that enhance our food supplies, reduce exposure to predators and natural dangers, and promote commerce. On average, the net benefits to humankind of domesticated nature have been positive. We have, of course, made mistakes, causing unforeseen changes in ecosystem attributes, while leaving few, if any, truly wild places on Earth. Going into the future, scientists can help humanity to domesticate nature more wisely by quantifying the tradeoffs among ecosystem services, such as how increasing the provision of one service may decrease ecosystem resilience and the provision of other services.  相似文献   
64.
65.
66.
Genetic determination of phenotypic variation in sickle cell trait   总被引:3,自引:0,他引:3  
Two genetic sources of variation influence the percentage of sickle cell hemoglobin found in heterozygotes. One factor is strongly related to the percentage of hemoglobin S in the carrier parent and appears to be determined by sickle hemoglobin isoalleles, whereas the other is related to racial background and may well be polygenic.  相似文献   
67.
68.
69.
70.
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