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   330篇
  免费   10篇
林业   75篇
农学   6篇
基础科学   3篇
  43篇
综合类   30篇
农作物   10篇
水产渔业   25篇
畜牧兽医   123篇
园艺   14篇
植物保护   11篇
  2023年   4篇
  2022年   3篇
  2021年   7篇
  2020年   4篇
  2019年   3篇
  2017年   5篇
  2016年   6篇
  2015年   4篇
  2014年   9篇
  2013年   10篇
  2012年   13篇
  2011年   17篇
  2010年   9篇
  2009年   11篇
  2008年   16篇
  2007年   18篇
  2006年   16篇
  2005年   11篇
  2004年   13篇
  2003年   12篇
  2002年   11篇
  2000年   4篇
  1998年   3篇
  1997年   4篇
  1993年   4篇
  1992年   5篇
  1987年   3篇
  1986年   5篇
  1985年   3篇
  1981年   4篇
  1978年   5篇
  1975年   4篇
  1970年   5篇
  1968年   2篇
  1955年   2篇
  1954年   2篇
  1948年   3篇
  1944年   2篇
  1943年   3篇
  1942年   2篇
  1941年   2篇
  1940年   3篇
  1938年   7篇
  1936年   8篇
  1935年   4篇
  1934年   4篇
  1931年   7篇
  1930年   3篇
  1928年   3篇
  1896年   2篇
排序方式: 共有340条查询结果,搜索用时 31 毫秒
91.
Rundschau     
Ohne Zusammenfassung  相似文献   
92.
93.
94.
95.
96.
A toy Australian shepherd dog was referred for bile peritonitis following excision of a biliary mucocele. Subsequent delayed gastric emptying was refractory to prokinetic therapy but responded to injection of botulinum toxin A into the muscularis layer of the pylorus; a novel therapy for delayed gastric emptying in dogs.  相似文献   
97.
Type III secreted "effector" proteins of bacterial pathogens play central roles in virulence, yet are notoriously difficult to identify. We used an in vivo genetic screen to identify 13 effectors secreted by the type III apparatus (called Hrp, for "hypersensitive response and pathogenicity") of the plant pathogen Pseudomonas syringae. Although sharing little overall homology, the amino-terminal regions of these effectors had strikingly similar amino acid compositions. This feature facilitated the bioinformatic prediction of 38 P. syringae effectors, including 15 previously unknown proteins. The secretion of two of these putative effectors was shown to be type III--dependent. Effectors showed high interstrain variation, supporting a role for some effectors in adaptation to different hosts.  相似文献   
98.
99.
Robotics researchers increasingly agree that ideas from biology and self-organization can strongly benefit the design of autonomous robots. Biological organisms have evolved to perform and survive in a world characterized by rapid changes, high uncertainty, indefinite richness, and limited availability of information. Industrial robots, in contrast, operate in highly controlled environments with no or very little uncertainty. Although many challenges remain, concepts from biologically inspired (bio-inspired) robotics will eventually enable researchers to engineer machines for the real world that possess at least some of the desirable properties of biological organisms, such as adaptivity, robustness, versatility, and agility.  相似文献   
100.
This paper is an evaluation of the sociological significance of the development and adoption of sustainable agricultural practices. The concept of “appropriationism” is introduced as a means of determining whether or not sustainable agriculture is an expression of class antagonisms in U. S. agriculture. “Appropriationism” is the process by which corporate agribusiness replaces natural processes with industrial products. A comparison of responses to farm crisis in the late 19th century and in the 1980s is employed as a heuristic device to determine the contemporary sociological significance of sustainable agriculture. Based on past experience and changes in key institutions over the past century, it is concluded that the development of sustainable agricultural practices will not significantly challenge the economic prerogatives of agribusiness and that the long-term process of the industrial appropriation of natural processes in agriculture will continue into the 21st century.  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