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   1276913篇
  免费   92768篇
  国内免费   1989篇
耳鼻咽喉   18189篇
儿科学   42262篇
妇产科学   37817篇
基础医学   187053篇
口腔科学   35382篇
临床医学   108132篇
内科学   251533篇
皮肤病学   26499篇
神经病学   99239篇
特种医学   49997篇
外国民族医学   366篇
外科学   197629篇
综合类   26517篇
现状与发展   1篇
一般理论   300篇
预防医学   92598篇
眼科学   29059篇
药学   97801篇
  1篇
中国医学   2496篇
肿瘤学   68799篇
  2018年   11819篇
  2015年   11618篇
  2014年   16002篇
  2013年   24362篇
  2012年   33571篇
  2011年   35958篇
  2010年   21221篇
  2009年   20023篇
  2008年   35006篇
  2007年   37972篇
  2006年   38520篇
  2005年   37813篇
  2004年   36405篇
  2003年   35395篇
  2002年   34942篇
  2001年   58100篇
  2000年   59590篇
  1999年   50694篇
  1998年   14234篇
  1997年   12810篇
  1996年   13076篇
  1995年   12347篇
  1994年   11758篇
  1993年   10861篇
  1992年   40988篇
  1991年   40366篇
  1990年   39886篇
  1989年   38710篇
  1988年   36112篇
  1987年   35351篇
  1986年   33726篇
  1985年   32139篇
  1984年   23924篇
  1983年   20818篇
  1982年   12378篇
  1981年   10929篇
  1980年   10204篇
  1979年   22637篇
  1978年   15877篇
  1977年   13729篇
  1976年   12971篇
  1975年   14201篇
  1974年   16682篇
  1973年   16076篇
  1972年   15318篇
  1971年   14231篇
  1970年   13214篇
  1969年   12732篇
  1968年   11980篇
  1967年   10478篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
The Authors examine the correlation between hypertensive disorders of pregnancy and fetal growth. The results of a study of 342 pregnancies, confirm a significant correlation between hypertension and fetal growth retardation. These findings, so evident in moderate and severe hypertension, have also been confirmed in cases of mild hypertension. The medical treatment also in the pregnancies with mild hypertension, and a larger utilisation of operative deliveries, determined a decrease in perinatal mortality and morbidity.  相似文献   
92.
93.
Background The appearance of eosinophils is a hallmark sign of the allergic late-phase response (LPR). Eosinophil cationic protein (ECP), a readily measurable product released from activated eosinophils, has so far not been evaluated in the ocular LPR. Objective Two sets of trials were performed in order to investigate changes of local and systemic eosinophil activity and their possible link with symptoms and hyper-reactivity in the allergic LPR in the eye. Methods In the first experiment, ECP was analysed in tears and serum and the clinical reaction was evaluated during a 72-h time–course after a single, high-dose allergen challenge out of season in one eye of 15 pollen-sensitized volunteers. In a second experiment, the hypothesis of an increased clinical response to an allergen challenge in an eye that had been provoked with allergen 48h previously was tested in nine sensitized individuals. Results In the first experiment, symptoms at 10 min and 2, 4, 6, 8 and 24 h significantly exceeded base line scores of the challenged eyes. Tear ECP was significantly elevated in challenged eyes compared to contralateral eyes at 6, 8 and 24 h. In addition, symptoms and ECP release correlated significantly at the 24-h evaluation. Serum ECP remained unchanged throughout the study period. In the second experiment, conjunctival hyperreactivity 48h after an allergen challenge was not confirmed. Conclusion ECP secretion occurs in the experimental ocular LPR and is in part associated with the magnitude of the clinical reaction, which suggests a truly pathogenic role of the activated eosinophil in pollen-induced allergic conjunctivitis.  相似文献   
94.
95.
96.
97.
98.
99.
100.
Transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (TES) of the human motor cortex produce a silent period (SP) following motor evoked potentials (MEPs). The early part of the SP can be explained by decreased alpha motor neuron excitability, whereas the late part is presumably due to suprasegmental mechanisms. In order to determine the level of the suprasegmental contribution to the generation of SPs, we recorded excitatory and inhibitory responses to TMS, TES, and percutaneous electrical brainstem stimulation (PBS) in the voluntarily activated first dorsal interosseous muscle of the hand. Stimulus intensities were set so that PBS and TES induced MEPs with areas equal to or larger than those of MEPs obtained with TMS. This procedure revealed that SPs were 49% and 83% shorter with TES and PBS, respectively, than with TMS. As TMS is more effective than TES or PBS in activating cortical interneurons, these findings support the idea that a significant component of the SP arises from intracortical mechanisms.  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