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   134203篇
  免费   10503篇
  国内免费   40篇
  144746篇
  2021年   1301篇
  2020年   1032篇
  2019年   1136篇
  2018年   2097篇
  2017年   1939篇
  2016年   2902篇
  2015年   3678篇
  2014年   4059篇
  2013年   5563篇
  2012年   6611篇
  2011年   6345篇
  2010年   4162篇
  2009年   3396篇
  2008年   5398篇
  2007年   5273篇
  2006年   5119篇
  2005年   4656篇
  2004年   4614篇
  2003年   4324篇
  2002年   4057篇
  2001年   5113篇
  2000年   4978篇
  1999年   3665篇
  1998年   1296篇
  1997年   1176篇
  1996年   1081篇
  1995年   1017篇
  1994年   974篇
  1993年   967篇
  1992年   2621篇
  1991年   2608篇
  1990年   2587篇
  1989年   2314篇
  1988年   2160篇
  1987年   2040篇
  1986年   1893篇
  1985年   1924篇
  1984年   1613篇
  1983年   1379篇
  1982年   1022篇
  1979年   1496篇
  1978年   1179篇
  1977年   1068篇
  1976年   1052篇
  1975年   1217篇
  1974年   1311篇
  1973年   1387篇
  1972年   1220篇
  1971年   1077篇
  1969年   972篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Power spectra and coherence function of EEG of various cortical areas of both hemispheres were analyzed in 9 patients with extremely protracted loss of consciousness. Five patients were in the state of posttraumatic apallic syndrome lasting for more than 4 years in one patient, and 4-9 months with successive lethal outcome in 4 patients. One patient for more than 2 years was in a state of areactivity to external signals. In 3 patients the process of recovery of consciousness and speech began in 1-2 months. At the apallic syndrome, only low-frequency EEG components were present in spectrograms, and the values of coherence function were sharply decreased. With recovering consciousness and speech, a gradual appearance of alpha-activity was observed as well as an increase of coherence values at the frequency of the alpha-rhythm. The recovery of intercentral EEG relations in the motor-verbal cortical area was shown to play a special role in further normalization of connections in the cerebral cortex.  相似文献   
92.
93.
94.
95.
96.
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   
97.
98.
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   
99.
100.
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