首页 | 官方网站   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   2335943篇
  免费   174967篇
  国内免费   3279篇
医药卫生   2514189篇
  2021年   18304篇
  2019年   19532篇
  2018年   27048篇
  2017年   20355篇
  2016年   22745篇
  2015年   25641篇
  2014年   36095篇
  2013年   53951篇
  2012年   74678篇
  2011年   79407篇
  2010年   47059篇
  2009年   44566篇
  2008年   74614篇
  2007年   79476篇
  2006年   80296篇
  2005年   77779篇
  2004年   74372篇
  2003年   71694篇
  2002年   69365篇
  2001年   108739篇
  2000年   111450篇
  1999年   93494篇
  1998年   26990篇
  1997年   23543篇
  1996年   22355篇
  1995年   22558篇
  1994年   20763篇
  1993年   19593篇
  1992年   71871篇
  1991年   70045篇
  1990年   68347篇
  1989年   65624篇
  1988年   60245篇
  1987年   59075篇
  1986年   55181篇
  1985年   52965篇
  1984年   39235篇
  1983年   33299篇
  1982年   19758篇
  1979年   35782篇
  1978年   25577篇
  1977年   21129篇
  1976年   20254篇
  1975年   21752篇
  1974年   26089篇
  1973年   24761篇
  1972年   23179篇
  1971年   22013篇
  1970年   20220篇
  1969年   19286篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
LUMBOVERTEBRAL SYNDROME AFTER EXTRADURAL BLOOD PATCH   总被引:2,自引:1,他引:1  
We describe a patient who developed an immobilizing lumbovertebralsyndrome after an extradural blood patch and who was hospitalizedwith a. suspected extradural abscess. An infectious aetiologyof the persistent backache could be excluded and the patientrecovered with analgesics and physiotherapy. The probable aetiologyis discussed.  相似文献   
995.
996.
Abstract: Establishment of mixed bone marrow chimerism in pig-to-primate transplantation, as a means of inducing specific immune tolerance, will require that both immune and nonimmune barriers be overcome. As a preliminary step in evaluating nonimmune barriers in this system, we have developed an in vitro model of engraftment in which long-term culture of porcine bone marrow-derived hematopoietic cells is supported on preformed primate bone marrow stromal layers. In the absence of cytokine supplementation, primate stromal cells were unable to support long-term porcine hematopoiesis in these cultures. Supplementation with porcine Steel Factor was required for long-term maintenance of hematopoietic progenitor cell content and total hematopoietic activity. Addition of porcine IL-3, in combination with porcine Steel Factor, increased long-term progenitor cell content and hematopoietic activity on primate stroma to levels comparable to that obtained in cultures on porcine stroma. The combination of porcine GM-CSF and Steel Factor increased progenitor cell content and hematopoietic activity early in the cultures, but had little effect in long-term cultures. The Steel Factor and IL-3 combination was species-specific in its action in these cultures, as the corresponding human cytokines were unable to effectively support long-term porcine hematopoiesis. Likewise, the combination of porcine cytokines had only minimal effects on long-term bone marrow culture of primate CD34+ cells I on primate stroma.  相似文献   
997.
To date, only 10 cases of distal penile gangrene in patients with chronic renal failure have been reported. This rare condition is believed to result from progressive vascular calcification due to secondary hyperparathyroidism in patients with chronic renal failure. We report an additional case of distal penile gangrene in a 41-year-old man who presented with chronic renal disease and pulmonary tuberculosis. Since some authors have emphasized that aggressive surgical treatment in such cases has a significant mortality rate, we took a more conservative approach to treatment.  相似文献   
998.
999.
Sensitivity of normotensive Wistar rats and NISAG rats (with hereditary arterial hypertension) to heat stress is compared at the organism and cell levels. High temperature sensitivity of NISAG rats correlates with a low content of the main heat shock protein HSP70. This relationship can serve as a biochemical marker of predisposition to arterial hypertension. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 8, pp. 171–173, August, 1997  相似文献   
1000.
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-23

京公网安备 11010802026262号