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   394篇
  免费   23篇
林业   13篇
农学   6篇
  41篇
综合类   62篇
农作物   17篇
水产渔业   10篇
畜牧兽医   251篇
园艺   4篇
植物保护   13篇
  2023年   4篇
  2021年   4篇
  2020年   9篇
  2019年   8篇
  2018年   9篇
  2017年   6篇
  2016年   3篇
  2015年   5篇
  2014年   9篇
  2013年   11篇
  2012年   19篇
  2011年   16篇
  2010年   10篇
  2009年   14篇
  2008年   18篇
  2007年   38篇
  2006年   17篇
  2005年   20篇
  2004年   21篇
  2003年   16篇
  2002年   22篇
  2001年   7篇
  2000年   6篇
  1999年   4篇
  1998年   7篇
  1997年   4篇
  1996年   6篇
  1991年   3篇
  1989年   6篇
  1988年   4篇
  1986年   4篇
  1985年   3篇
  1983年   2篇
  1979年   4篇
  1978年   2篇
  1976年   3篇
  1975年   2篇
  1973年   3篇
  1972年   5篇
  1971年   2篇
  1970年   2篇
  1969年   4篇
  1965年   2篇
  1956年   2篇
  1916年   2篇
  1915年   2篇
  1902年   2篇
  1901年   3篇
  1898年   2篇
  1892年   4篇
排序方式: 共有417条查询结果,搜索用时 8 毫秒
91.
92.
93.
94.
95.
96.
97.
98.
In vitro shoots of six pear (Pyrus communis L.) cultivars, ‘Conference’, ‘Doyennéd'Hiver’, ‘Passe Crassane’, ‘Bartlett’, ‘AbbéFetel’ and ‘Butirra Precoce Morettini’ were irradiated with gamma rays (3.5 Gy). After three subcultures, microcuttings from the irradiated shoots and from additional non-irradiated microcuttings were rooted to establish plants for survey orchards. All trees were individually observed for variation in fruit traits and for productivity. Trees were selected for improved characters related to production such as early bearing and consistent productivity. Variations observed in fruit appearance concerned degree of russeting, fruit shape and size. The frequencies of the observed variations in fruit traits depended on the cultivar, ranging from 0.81% in ‘Doyennéd'Hiver’ to 3.64% in ‘Passe Crassane’. Of the 97 variants selected, only two showed chimeral behavior. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
99.
National beef market basket survey   总被引:1,自引:0,他引:1  
Beef retail cases in supermarkets in 12 cities across the United States were surveyed for fat thickness measurements, cut representation, package weights and counts, and case space allocation. Randomly selected retail cuts were purchased and transported to Texas A&M University, where they were dissected into separable components. Samples of ground beef were obtained for chemical analysis. Over 42% of the beef retail cuts had no external fat, and approximately 75% of all cuts were boneless. The overall mean fat thickness for all retail cuts in the beef case was .31 cm, and the overall mean fat thickness for steaks and roasts from the major primals - chuck, rib, loin, and round - was .38 cm. The average percentage of separable lean was 79.0%, separable fat was 12.3%, and bone and connective tissue was 8.7%. Retail cuts had more than twice as much separable seam fat as separable external fat. Beef steaks and roasts had 27.4% less separable fat than values from USDA Agriculture Handbook 8-13. Of the ground beef surveyed, 37% was regular, 40% was lean, and over 22% was extra lean. Retail ground beef had approximately 10% less fat than values from USDA Agriculture Handbook 8-13.  相似文献   
100.
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