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   1283794篇
  免费   93378篇
  国内免费   2011篇
耳鼻咽喉   18250篇
儿科学   42525篇
妇产科学   37942篇
基础医学   187899篇
口腔科学   35652篇
临床医学   108871篇
内科学   252622篇
皮肤病学   26594篇
神经病学   99861篇
特种医学   50306篇
外国民族医学   366篇
外科学   198783篇
综合类   26631篇
现状与发展   1篇
一般理论   304篇
预防医学   93272篇
眼科学   29189篇
药学   98148篇
  1篇
中国医学   2500篇
肿瘤学   69466篇
  2018年   11916篇
  2015年   11698篇
  2014年   16146篇
  2013年   24548篇
  2012年   33836篇
  2011年   36240篇
  2010年   21361篇
  2009年   20163篇
  2008年   35250篇
  2007年   38232篇
  2006年   38797篇
  2005年   38045篇
  2004年   36640篇
  2003年   35627篇
  2002年   35184篇
  2001年   58303篇
  2000年   59820篇
  1999年   50905篇
  1998年   14319篇
  1997年   12881篇
  1996年   13121篇
  1995年   12424篇
  1994年   11818篇
  1993年   10916篇
  1992年   41187篇
  1991年   40558篇
  1990年   40074篇
  1989年   38906篇
  1988年   36274篇
  1987年   35545篇
  1986年   33899篇
  1985年   32296篇
  1984年   24050篇
  1983年   20923篇
  1982年   12440篇
  1981年   10996篇
  1980年   10255篇
  1979年   22743篇
  1978年   15956篇
  1977年   13798篇
  1976年   13035篇
  1975年   14260篇
  1974年   16751篇
  1973年   16145篇
  1972年   15388篇
  1971年   14295篇
  1970年   13272篇
  1969年   12787篇
  1968年   12023篇
  1967年   10521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