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   70篇
  免费   44篇
林业   1篇
  1篇
综合类   22篇
畜牧兽医   87篇
植物保护   3篇
  2020年   3篇
  2017年   1篇
  2016年   2篇
  2015年   1篇
  2013年   2篇
  2012年   2篇
  2010年   1篇
  2009年   3篇
  2008年   1篇
  2005年   1篇
  2004年   1篇
  2003年   1篇
  2002年   2篇
  2001年   1篇
  1999年   3篇
  1998年   4篇
  1997年   1篇
  1996年   2篇
  1995年   1篇
  1994年   2篇
  1993年   1篇
  1992年   2篇
  1991年   1篇
  1990年   2篇
  1989年   3篇
  1988年   1篇
  1987年   3篇
  1985年   1篇
  1984年   1篇
  1980年   2篇
  1978年   4篇
  1977年   2篇
  1976年   2篇
  1975年   4篇
  1974年   4篇
  1973年   5篇
  1972年   6篇
  1971年   2篇
  1970年   9篇
  1969年   6篇
  1968年   4篇
  1942年   1篇
  1924年   1篇
  1910年   1篇
  1907年   2篇
  1903年   1篇
  1900年   2篇
  1899年   1篇
  1894年   2篇
  1892年   1篇
排序方式: 共有114条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
Polioencephalomalacia (PEM), a disease first described in the United States and related to intensive beef production, appeared in Cuba coincident with the use of a new, molasses-urea-based diet to fatten bulls. Because the only experimental means so far of reproducing PEM has been with amprolium, a structural analog of thiamin, the present study attempted to induce the disease using the molasses-urea-based diet. Six Holstein bulls (200-300 kg) were studied during consumption of three successive diets: 1) commercial molasses-urea-restricted forage diet of Cuban feedlots, 2) a period in which forage was gradually withdrawn and 3) a forage-free diet composed only of molasses, urea and fish meal. PEM was reproduced in this way. At ten-day intervals, blood concentrations of glucose, lactate, pyruvate and urea were measured, as well as when clinical signs of PEM appeared. The signs, clinical course and lesions of the experimentally induced disease were comparable to those of field cases. The biochemical results suggested a block in pyruvate oxidation as in PEM elsewhere in the world. No evidence existed of urea intoxication. In addition, brain and liver concentration of total thiamin from field cases and normal animals were found to be similar.  相似文献   
6.
7.
Formation of a Reservoir of Sperm in the Oviduct   总被引:2,自引:0,他引:2  
A reservoir of sperm in the initial segment of the oviduct has been found in several species of domestic and laboratory mammals. Evidently, the reservoir serves to ensure successful fertilization by providing the appropriate number of sperm in the appropriate physiological state for fertilizing oocytes soon after they enter the oviduct. Recent evidence indicates that sperm are trapped in the reservoir by binding to specific carbohydrate moieties on the surface of the mucosal epithelium of the oviduct. A bovine seminal plasma protein has been identified that associates with sperm and confers on them the capacity to bind to the carbohydrate moiety.  相似文献   
8.
9.
10.
The thiamin status (thiamin concentration in whole blood, plasma, and erythrocytes; erythrocyte transketolase activity) of normal cattle consuming varying diets did not differ from that of cattle with polioencephalomalacia or lead poisoning. Dairy cattle had higher ruminal content of thiamin and lower thiamin destroying activity than did beef cattle. Renal oxalosis was no more frequent in cattle which had polioencephalomalacia than in postnatal calves. In normal beef cattle, approximately 75% of total blood thiamin is in erythrocytes and the remainder in plasma.  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