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   97739篇
  免费   7724篇
  国内免费   34篇
  105497篇
  2021年   853篇
  2018年   1310篇
  2017年   1218篇
  2016年   1643篇
  2015年   1748篇
  2014年   2108篇
  2013年   3000篇
  2012年   3280篇
  2011年   3386篇
  2010年   2519篇
  2009年   2118篇
  2008年   3081篇
  2007年   3025篇
  2006年   2847篇
  2005年   2689篇
  2004年   2680篇
  2003年   2564篇
  2002年   2389篇
  2001年   4420篇
  2000年   4177篇
  1999年   3235篇
  1998年   1049篇
  1997年   1039篇
  1996年   918篇
  1995年   838篇
  1993年   829篇
  1992年   2453篇
  1991年   2460篇
  1990年   2460篇
  1989年   2204篇
  1988年   2066篇
  1987年   1982篇
  1986年   1829篇
  1985年   1822篇
  1984年   1503篇
  1983年   1301篇
  1982年   934篇
  1981年   874篇
  1979年   1440篇
  1978年   1131篇
  1977年   1016篇
  1976年   975篇
  1975年   1163篇
  1974年   1258篇
  1973年   1342篇
  1972年   1187篇
  1971年   1044篇
  1970年   925篇
  1969年   955篇
  1968年   836篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
The perfusion procedure described in this paper produces high quality impregnation of pig visual and somatosensory cortical neurons with a Golgi-Cox solution. Starting within 30 min after death, pig heads were perfused with a fixative solution composed of a mixture (v/v) of liquid phenol, 5%; formalin, 14%; ethylene glycol, 25%; methanol, 28%; and water, 28% for two periods of 4 hr each. After perfusion, the heads were chilled for at least 18 hr. The entire brain was removed from the skull and then placed in 10% buffered formalin, where it remained for at least 10 days before taking the blocks that were to be immersed in the Golgi-Cox solution. Three weeks spent in the Golgi-Cox solution typically produced uniform neuron impregnation. The tissue blocks were then embedded in celloidin and sectioned at 120 micron. This procedure avoids the following difficulties: Golgi-Cox methods that produced excellent results with rodent or primate tissue were unsuccessful with pig tissue, placing fresh tissue in Golgi-Cox solution resulted in incomplete neuron impregnation, and immersion fixation in 10% buffered formalin without perfusion resulted in excessive staining of glia.  相似文献   
92.
93.
The paper is concerned with analysis of the results of intraoperative phlebotesticulography, performed in 50 patients with varicocele of degree I-II during Ivanissevich's operation. The effect of surgical intervention was shown to depend upon the quality of ligation of the testicular vein, some parts of which are anastomosed between themselves. The localization of this anastomosis is revealed by means of intraoperative phlebotesticulography, which permits increasing the results of surgical treatment and predicting a course of a postoperative period.  相似文献   
94.
95.
96.
97.
Summary Responses of lentil in unsterile soils at low, medium and high levels of plant available soil P toGlomus fasciculatum inoculation were evaluated. It was observed that growth, dry matter accumulation, nodulation, and nitrogen fixation were considerably improved in VAM inoculated plants over uninoculated control at low and medium levels of plant available soil P.  相似文献   
98.
99.
100.
The combination of alpha interferon and vinblastine has been reported to yield a response rate of 30-40% in previously untreated patients with metastatic renal cell carcinoma. This combination was given to nine patients with advanced metastatic renal carcinoma after they failed or relapsed on alpha-interferon alone, to attempt to evaluate the role of vinblastine in this combination. Neither complete nor partial response was observed. Two patients had disease stabilization for two and seven months. Our preliminary results suggest that vinblastine did not add to the efficacy of interferon in this group of patients.  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