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   322697篇
  免费   17824篇
  国内免费   1417篇
林业   24809篇
农学   14559篇
基础科学   3247篇
  47817篇
综合类   45295篇
农作物   17622篇
水产渔业   18203篇
畜牧兽医   137419篇
园艺   6804篇
植物保护   26163篇
  2019年   3911篇
  2018年   4477篇
  2017年   4967篇
  2016年   5188篇
  2015年   4726篇
  2014年   6032篇
  2013年   16793篇
  2012年   8458篇
  2011年   10912篇
  2010年   8421篇
  2009年   8707篇
  2008年   9975篇
  2007年   9165篇
  2006年   9539篇
  2005年   8780篇
  2004年   8468篇
  2003年   8191篇
  2002年   7625篇
  2001年   8458篇
  2000年   8176篇
  1999年   7154篇
  1998年   4403篇
  1997年   4429篇
  1996年   4172篇
  1995年   4791篇
  1994年   4275篇
  1993年   3950篇
  1992年   5840篇
  1991年   6193篇
  1990年   6022篇
  1989年   5933篇
  1988年   5375篇
  1987年   5484篇
  1986年   5537篇
  1985年   5521篇
  1984年   4989篇
  1983年   4547篇
  1982年   3531篇
  1981年   3349篇
  1980年   3283篇
  1979年   4417篇
  1978年   3838篇
  1977年   3415篇
  1976年   3202篇
  1975年   3138篇
  1974年   3797篇
  1973年   3760篇
  1972年   3507篇
  1971年   3355篇
  1970年   3197篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
105.
A brief discussion of those aspects of neonatal physiology that pertain to anesthetic risk and selection of anesthetic techniques is followed by discussion of suggested techniques for anesthetic management in healthy foals. Preoperative preparation and management of foals with selected serious surgical conditions are also considered.  相似文献   
106.
Over 54,600 ha of table grapes (Vitis vinifera), mainly cvs. ‘Thompson Seedless’, ‘Flame Seedless’ and ‘Redglobe’, are planted in Chile. Almost the entire production is exported to the USA, Europe, Asia, or one of several Latin American countries, which typically requires 15–40 d of maritime transportation. During this period, several physical, physiological, and pathological factors cause table grape deterioration. Because berry size is the main quality factor in international markets, farmers often overuse the growth regulators, gibberellic acid (GA3) and forchlorfenuron (CPPU), in an effort to increase berry size. We examined the effect of preharvest growth regulators on seedless (‘Thompson Seedless’, and ‘Ruby Seedless’) and seeded (‘Redglobe’) table grape cultivars during cold (0 °C) storage plus a shelf life period of 3 d at 20 °C. The overuse of GA3, eight instead of two GA3 applications on Thompson Seedless, and the use of one GA3 application on Redglobe and ‘Ruby Seedless’, increased berry pedicel thickness and lowered cuticle content but induced shatter and predisposed grapes to gray mold caused by Botrytis cinerea. In contrast, CPPU increased berry pedicel thickness and cuticle content but did not increase shatter or gray mold incidence. Clusters that were subjected to overuse of combined GA3 and CPPU were highly sensitive to shatter, had the thickest pedicel, and developed a high gray mold incidence during cold storage. Hairline, a fine cracking developed during cold storage, was induced on ‘Thompson Seedless’ and ‘Ruby Seedless’ by growth regulators, but no hairline occurred on ‘Redglobe’ table grapes. Therefore, berry quality during cold storage is greatly influenced by growth regulator management in the vineyard.  相似文献   
107.
Disseminated Aspergillus terreus infection was diagnosed in ten previously healthy adult dogs--nine German shepherds and one dalmatian. The disease was characterized by the presence of multiple granulomas and infarcts in a wide range of organs. The kidney, spleen, and skeletal system were most commonly and severely affected. Fungal hyphae were demonstrated in large numbers within granulomas and thrombi, and A. terreus was readily isolated by culture. This disseminated mycosis appears unique; in this series of cases there was no apparent predisposing factor, portal of entry, or primary focus for dissemination of the infection.  相似文献   
108.
109.
110.
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