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   175篇
  免费   2篇
林业   3篇
农学   8篇
基础科学   4篇
  11篇
综合类   21篇
水产渔业   34篇
畜牧兽医   92篇
园艺   2篇
植物保护   2篇
  2020年   2篇
  2016年   3篇
  2015年   1篇
  2014年   3篇
  2013年   5篇
  2012年   3篇
  2011年   1篇
  2010年   1篇
  2009年   1篇
  2008年   8篇
  2007年   2篇
  2006年   3篇
  2005年   6篇
  2004年   9篇
  2003年   1篇
  2002年   4篇
  2001年   3篇
  2000年   5篇
  1999年   6篇
  1998年   3篇
  1997年   2篇
  1996年   2篇
  1995年   2篇
  1994年   3篇
  1993年   1篇
  1992年   6篇
  1991年   12篇
  1990年   4篇
  1989年   6篇
  1988年   4篇
  1987年   5篇
  1985年   9篇
  1983年   6篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1978年   3篇
  1977年   4篇
  1976年   1篇
  1975年   4篇
  1974年   5篇
  1973年   6篇
  1972年   6篇
  1971年   2篇
  1970年   1篇
  1966年   4篇
  1965年   1篇
  1959年   1篇
  1863年   1篇
排序方式: 共有177条查询结果,搜索用时 15 毫秒
171.
Neurological examination in equine practice, physiological findings and pathological disturbances are described. Because of the sizes of the horse the neurological examination is more difficult than in small animals. The examination of cerebrospinal fluid is a worthful completion and is able to refer to the etiology of a certain disease. The technique of the puncture of cerebrospinal fluid is described.  相似文献   
172.
173.
An intramural radiolucent band in the stomach wall can be seen on abdominal radiographs of cats without concurrent clinical gastrointestinal signs. A retrospective study of cats with normal abdominal radiographs and computed tomography (CT) was performed to determine the prevalence of this finding. This gastric radiolucent band was seen in 13 of 37 (35%) radiographs. There was no relationship between age, weight and relative obesity and the presence of this radiolucent band. Using CT, an intramural hypoattenuating layer was detected in the stomach wall of four of 15 (27%) cats. The intramural radiolucent band was visible on the radiographs in all four of those cats. This radiographic and CT finding was histologically determined to be normal fat in the gastric submucosa in one cat cadaver.  相似文献   
174.
No consistent explanation has been found for the variability in the thiaminase activity of alewives Alosa pseudoharengus despite the role of alewife thiaminase in large-scale salmonine mortality in the Laurentian Great Lakes. We conducted experiments to evaluate the effect of two stressors, reduced salt content in the water and food limitation, on alewife thiaminase activity. Alewives were subjected to treatments in replicated tanks in which conductivity was lowered (< 100 microS/cm) for 8 d and feeding was limited for 39 d. Circulating white blood cells, plasma cortisol, plasma glucose, and whole-body thiaminase were measured in individual alewives to assess their response to these experimental treatments. Alewives from the controls had significantly larger numbers of circulating white blood cells than those in the salt-reduced and food-limited treatments (24,000 and 19,000 cells/microL and 11,000 and 9,000 cells/microL for alewives from the two control and salt-reduced treatment tanks, respectively, and 34,000 and 30,000 cells/microL and 21,000 and 16,000 cells/microL for alewives from the two control and food-limited treatment tanks). No significant differences in alewife thiaminase activity were found between treatment fish and their controls. The mean thiaminase activity in the alewives studied increased from 6,900 to 16,000 pmol x g(-1) x min(-1) from the time of their collection in Cayuga Lake to the start of laboratory experiments 1.5-2.5 years later; the latter value was more than twice that of previously reported levels of thiaminase activity from alewives collected in the wild. These data suggest that the variability in alewife thiaminase is not related to stress from salt reduction or food limitation, but laboratory holding conditions significantly increased thiaminase through a mechanism not evaluated by our experimental treatments.  相似文献   
175.
176.
Sea level rise, deltaic progradation, and floodplain aggradation have changed the landscape in the vicinity of ancient Troy during the past 10,000 years. With the waning of the last major world glaciation and resultant sea level rise and fluctuation, a marine embayment protruded nearly 10 kilometers south of the site of Troy at Hisarlik in the Troad of northwest Turkey. As the sea approached its present level approximately 6000 years ago, fluvial and marine deposition caused a northerly migration of the delta and floodplain of the Scamander and Simois Rivers past the site of Troy toward the present-day coast about 6 kilometers north of the site. In view of these major changes in morphology, interpretations of ancient geographies related to historical or historical-mythological settings must be changed. A number of paleogeographic maps have been reconstructed with the use of subsurface data that records the continuing landscape change since the first occupancy of the site at Troy 5000 years ago. These show that ancient Troy was located on an embayment of the sea. If the Trojan War occurred, then the axis of the battlefield and associated events must be relocated to the south and west of Troy.  相似文献   
177.
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