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   1279798篇
  免费   100298篇
  国内免费   1996篇
耳鼻咽喉   18443篇
儿科学   44404篇
妇产科学   35077篇
基础医学   182559篇
口腔科学   33622篇
临床医学   111596篇
内科学   259156篇
皮肤病学   28144篇
神经病学   100761篇
特种医学   51360篇
外国民族医学   660篇
外科学   196804篇
综合类   27104篇
现状与发展   1篇
一般理论   381篇
预防医学   95891篇
眼科学   27929篇
药学   94961篇
  2篇
中国医学   2423篇
肿瘤学   70814篇
  2018年   13193篇
  2017年   10012篇
  2016年   10953篇
  2015年   12446篇
  2014年   17261篇
  2013年   26322篇
  2012年   36223篇
  2011年   38237篇
  2010年   22907篇
  2009年   21922篇
  2008年   36822篇
  2007年   39476篇
  2006年   39714篇
  2005年   38665篇
  2004年   37766篇
  2003年   36630篇
  2002年   35972篇
  2001年   64114篇
  2000年   66626篇
  1999年   56501篇
  1998年   15166篇
  1997年   13796篇
  1996年   14245篇
  1995年   13476篇
  1994年   12802篇
  1993年   11814篇
  1992年   44610篇
  1991年   43538篇
  1990年   42281篇
  1989年   40174篇
  1988年   36949篇
  1987年   36296篇
  1986年   33667篇
  1985年   32328篇
  1984年   24178篇
  1983年   20300篇
  1982年   11759篇
  1981年   10719篇
  1980年   9539篇
  1979年   21374篇
  1978年   14840篇
  1977年   12562篇
  1976年   11714篇
  1975年   12649篇
  1974年   14696篇
  1973年   14145篇
  1972年   12976篇
  1971年   11761篇
  1970年   11078篇
  1969年   10062篇
排序方式: 共有10000条查询结果,搜索用时 750 毫秒
931.
932.
933.
Results of an examination of 39 patients are described and critically assessed. An analysis of the resolving power of the method of ultrasonic angiography in pathological formations of major vessels of the neck is given.  相似文献   
934.
935.
936.
The behavioural and physiological consequences of social status and reciprocal fighting in resident-intruder dyads of Long Evans male rats were evaluated. Before a chronic cohabitation of 10 days, residents and intruders were individually housed for one month to increase their aggressiveness. Control animals included isolates, i.e., animals kept individually housed throughout the experiment and pair-housed rats, i.e., pairs of rats housed together from their rats in the laboratory. In 19 out of 20 dyads, a clear dominance relationship developed with an advantage to the resident in 68% of the cases. Dominants showed more exploratory activity than subordinates in a open-field test at the end of the cohabitation period; subordinates groomed longer than animals from other experimental groups. Dominants had lower pain thresholds than individually and pair-housed animals. Both dominants and subordinates had higher tyrosine hydroxylase enzymatic activities in the left adrenal than isolated and pair-housed rats. Subordinates lost body weight and had higher plasma corticosteroid concentrations than animals from the other experimental groups. In addition, they had smaller thymus glands and reduced spleen lymphocyte responses to mitogenic stimulation in vitro, in comparison to dominant animals. These results show that subordination in the dyadic resident-intruder paradigm leads to a complex syndrome of behavioural and physiological changes, some of which may be modulated by the intensity of aggressive interactions.  相似文献   
937.
The uptake of the phenanthridinium ethidium by the trypanosomatids Crithidia fasciculata and Leptomonas seymouri was studied. The time course of uptake of ethidium was biphasic for both organisms, consisting of an initial rapid phase and a protracted slow phase. The characteristics of these phases were consistent with the hypothesis that the initial phase represented specific external binding, while the second phase represented transport into the cells. In L. seymouri the transport phase was inhibited by inhibitors of energy transduction and putative inhibitors of a transport ATPase. Ethidium transport could not be saturated over a large concentration range of ethidium. Phenanthridiniums and related compounds displayed both inhibitory and stimulatory effects on ethidium transport.  相似文献   
938.
We describe a case of pathologic jealousy (Othello syndrome) in a patient with Parkinson disease, which abated after discontinuing amantadine. We indicate that early recognition and treatment of the syndrome in this disease may avert physical violence. We also believe that our report further suggests a link between this specific behavioral disorder and dopaminergic activity.  相似文献   
939.
Behavioral state-specific changes in human hippocampal theta activity   总被引:1,自引:0,他引:1  
Although there has been extensive examination of the behavioral and physiologic correlates of hippocampal theta activity in animals, the human literature consists of a single case study. We investigated the differential effects of four behavioral states on human hippocampal theta activity in 16 epilepsy surgery patients. Behavioral conditions included resting eyes closed (RC), resting eyes open (RO), eyes open with auditory word activation (AW), and eyes open with visuospatial activation (VS). Hippocampal theta activity decreased during both RO and VS compared to both RC and AW. There were reciprocal changes in delta activity. Comparisons of RO to VS and of RC to AW were nonsignificant. The results demonstrate state-specific changes in human hippocampal theta and are consistent with the animal literature that relates hippocampal theta to sensorimotor integration and forebrain volitional mechanisms.  相似文献   
940.
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