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   553009篇
  免费   69445篇
  国内免费   188篇
  2016年   6058篇
  2015年   8594篇
  2014年   10298篇
  2013年   14526篇
  2012年   16194篇
  2011年   16342篇
  2010年   10745篇
  2009年   10191篇
  2008年   14584篇
  2007年   15422篇
  2006年   14374篇
  2005年   14082篇
  2004年   13915篇
  2003年   13504篇
  2002年   12992篇
  2001年   23027篇
  2000年   23384篇
  1999年   18891篇
  1998年   7018篇
  1997年   7308篇
  1996年   7126篇
  1995年   6809篇
  1994年   6809篇
  1993年   6714篇
  1992年   16473篇
  1991年   16329篇
  1990年   16017篇
  1989年   15557篇
  1988年   14571篇
  1987年   14005篇
  1986年   13089篇
  1985年   13306篇
  1984年   11286篇
  1983年   9957篇
  1982年   7783篇
  1981年   7374篇
  1980年   6947篇
  1979年   11177篇
  1978年   8744篇
  1977年   8090篇
  1976年   7681篇
  1975年   8423篇
  1974年   8764篇
  1973年   8566篇
  1972年   8057篇
  1971年   7009篇
  1970年   6183篇
  1969年   5818篇
  1968年   5319篇
  1967年   4614篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
191.
192.
193.
194.
195.
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   
196.
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   
197.
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   
198.
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   
199.
200.
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