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   540016篇
  免费   68027篇
  国内免费   177篇
  608220篇
  2016年   5943篇
  2015年   8490篇
  2014年   10099篇
  2013年   14106篇
  2012年   15817篇
  2011年   16001篇
  2010年   10496篇
  2009年   9879篇
  2008年   14059篇
  2007年   14814篇
  2006年   13766篇
  2005年   13295篇
  2004年   13237篇
  2003年   12747篇
  2002年   12288篇
  2001年   22846篇
  2000年   23309篇
  1999年   18732篇
  1998年   6801篇
  1997年   7130篇
  1996年   6922篇
  1995年   6662篇
  1994年   6644篇
  1993年   6575篇
  1992年   16318篇
  1991年   16199篇
  1990年   15860篇
  1989年   15420篇
  1988年   14421篇
  1987年   13868篇
  1986年   12971篇
  1985年   13135篇
  1984年   11035篇
  1983年   9754篇
  1982年   7555篇
  1981年   7072篇
  1980年   6642篇
  1979年   11010篇
  1978年   8568篇
  1977年   7885篇
  1976年   7503篇
  1975年   8302篇
  1974年   8602篇
  1973年   8442篇
  1972年   7983篇
  1971年   6947篇
  1970年   6080篇
  1969年   5740篇
  1968年   5241篇
  1967年   4547篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
181.
182.
183.
184.
185.
The relations between the saccus lacrimalis and different portions of the musculus orbicularis oculi were studied in orbital regions of human fetuses sectioned into numbered series. No insertions of the pars lacrimalis or Horner's muscle on the saccus were found. These muscular fibres pass along the dorsal wall of the saccus and are separated from it by the reflex tendon of the ligamentum palpebrale mediale. The only muscular fibres that insert on the saccus are those that approach the anterior face of the saccus and the fornix. The fibres that insert on the anterior face proceed from the deep bundles of the pars preseptalis of the lower eyelids, and those that insert on the fornix derive from the deep bundles of the pars preseptalis of the upper eyelid.  相似文献   
186.
Using hot alkaline solution, the elastic laminae were extracted from aortas and observed with scanning electron microscopy. Vascular structures were found in the elastin layers of the tunica media in descending thoracic aortas of sheep, dogs, and pigs, and these tube-like structures were filled with elastomer which was injected through the heart of the animal in vivo. Sub-intimal microvessels were also found to be filled with the elastomer and it is concluded that vasa vasorum can exist close to the internal elastic lamina in these animals.  相似文献   
187.
C R Murphy  J G Swift 《Acta anatomica》1983,116(2):174-179
The proteolytic enzyme, pronase, was injected into the uterine lumen of rats. This treatment removed half the intramembranous particles (IMPs) from the apical plasma membrane of the uterine epithelial cells but tight junctions of these cells were unaffected. We conclude that at least some of the IMPs are proteinaceous in nature and suggest that IMPs not affected by pronase may be deeply embedded in the lipid bilayer.  相似文献   
188.
Two internal herinias of the intestines were found in adult males. One was a large translucent avascular membranous sac contining the small intestine from the duodenojejunal flexure to a point 6 in. proximal to the ileocaecal junction. The other was a peritoneal sac enclosing the small intestine, appendix, caecum and 6 in. of the ascending colon. The mesenteric and colic vessels were normal. Both hernias conformed to PAPEZ's concept of the so-called paraduodenal hernia that the hernial sac is derived from the umbilical coelom. The authors suggest that most of the so-called paraduodenal hernias are derived from the embryonic umbilical peritoneal diverticulum rather than from the peritoneal recesses or mesentery of the colon.  相似文献   
189.
190.
The liver and kidney of rat underwent severe histopathological lesions when treated with a single bolus dose of carbendazim, a fungicide, particularly affecting the hepatocytes and the renal corpuscles, respectively. The effects appear to be manifestations of the microtubule-disrupting activity of carbendazim. Treatment of carbendazim-treated rats with the powder of tuberous root of Withania somnifera (Ashwagandha) for 48 days resulted in complete cure of these organs. The results indicate that Withania somnifera would be an effective curative for carbendazim-induced histopathological changes in the liver and kidney.  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