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   837669篇
  免费   104004篇
  国内免费   351篇
  2016年   9208篇
  2015年   13029篇
  2014年   15352篇
  2013年   22037篇
  2012年   24345篇
  2011年   24843篇
  2010年   16519篇
  2009年   15503篇
  2008年   22028篇
  2007年   22941篇
  2006年   21321篇
  2005年   20786篇
  2004年   20352篇
  2003年   19953篇
  2002年   19190篇
  2001年   36221篇
  2000年   36786篇
  1999年   29407篇
  1998年   10738篇
  1997年   11478篇
  1996年   10935篇
  1995年   10416篇
  1994年   10332篇
  1993年   10314篇
  1992年   25496篇
  1991年   25184篇
  1990年   24401篇
  1989年   23960篇
  1988年   22149篇
  1987年   21441篇
  1986年   20135篇
  1985年   20264篇
  1984年   17015篇
  1983年   14942篇
  1982年   11605篇
  1981年   10612篇
  1980年   10098篇
  1979年   16788篇
  1978年   13184篇
  1977年   12151篇
  1976年   11515篇
  1975年   12701篇
  1974年   13195篇
  1973年   13022篇
  1972年   12125篇
  1971年   10793篇
  1970年   9328篇
  1969年   8867篇
  1968年   8055篇
  1967年   7083篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
311.
312.
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   
313.
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   
314.
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   
315.
D Roberts 《Acta anatomica》1978,101(2):160-169
Retention of a retromandibular space has necessitated developing a system of mandibular protrusion in hominid species. It is possible that mandibular protrusion can be effected by a single muscle-the lateral pterygoid-and the motion controlled by the excentrically placed mandibular suspensory ligaments. The elasticity of the ligaments produces an integrity maintenance force between the articular condyle and eminence which is normally of minimal size. Excessive craniofacial flexion, or the retention of a juvenile configuration of the mandible, could result in increasing this integrity maintenance force and cause crepitation and clicking. Ajustment of the ligaments could reduce these pathological manifestations.  相似文献   
316.
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   
317.
318.
319.
320.
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