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   5730326篇
  免费   419716篇
  国内免费   16380篇
耳鼻咽喉   81901篇
儿科学   185531篇
妇产科学   154148篇
基础医学   840982篇
口腔科学   162186篇
临床医学   531966篇
内科学   1042034篇
皮肤病学   133708篇
神经病学   469290篇
特种医学   221072篇
外国民族医学   1396篇
外科学   854702篇
综合类   158114篇
现状与发展   24篇
一般理论   3183篇
预防医学   478795篇
眼科学   138536篇
药学   410415篇
  29篇
中国医学   14519篇
肿瘤学   283891篇
  2021年   57769篇
  2019年   59917篇
  2018年   78615篇
  2017年   60460篇
  2016年   67286篇
  2015年   78704篇
  2014年   113322篇
  2013年   179292篇
  2012年   166691篇
  2011年   179865篇
  2010年   139440篇
  2009年   136123篇
  2008年   164402篇
  2007年   177941篇
  2006年   183934篇
  2005年   177890篇
  2004年   177740篇
  2003年   166841篇
  2002年   155278篇
  2001年   229058篇
  2000年   227616篇
  1999年   201519篇
  1998年   80065篇
  1997年   73279篇
  1996年   71303篇
  1995年   66652篇
  1994年   60628篇
  1993年   55920篇
  1992年   150533篇
  1991年   145964篇
  1990年   141641篇
  1989年   137810篇
  1988年   126994篇
  1987年   124980篇
  1986年   118144篇
  1985年   114853篇
  1984年   91008篇
  1983年   79594篇
  1982年   56063篇
  1981年   51743篇
  1980年   48375篇
  1979年   81985篇
  1978年   62558篇
  1977年   54314篇
  1976年   50917篇
  1975年   53047篇
  1974年   60898篇
  1973年   58415篇
  1972年   54814篇
  1971年   51272篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
AimsWe previously showed that the protective effects of endothelial progenitor cells (EPCs)‐released exosomes (EPC‐EXs) on endothelium in diabetes. However, whether EPC‐EXs are protective in diabetic ischemic stroke is unknown. Here, we investigated the effects of EPC‐EXs on diabetic stroke mice and tested whether miR‐126 enriched EPC‐EXs (EPC‐EXsmiR126) have enhanced efficacy.MethodsThe db/db mice subjected to ischemic stroke were intravenously administrated with EPC‐EXs 2 hours after ischemic stroke. The infarct volume, cerebral microvascular density (MVD), cerebral blood flow (CBF), neurological function, angiogenesis and neurogenesis, and levels of cleaved caspase‐3, miR‐126, and VEGFR2 were measured on day 2 and 14.ResultsWe found that (a) injected EPC‐EXs merged with brain endothelial cells, neurons, astrocytes, and microglia in the peri‐infarct area; (b) EPC‐EXsmiR126 were more effective than EPC‐EXs in decreasing infarct size and increasing CBF and MVD, and in promoting angiogenesis and neurogenesis as well as neurological functional recovery; (c) These effects were accompanied with downregulated cleaved caspase‐3 on day 2 and vascular endothelial growth factor receptor 2 (VEGFR2) upregulation till day 14.ConclusionOur results indicate that enrichment of miR126 enhanced the therapeutic efficacy of EPC‐EXs on diabetic ischemic stroke by attenuating acute injury and promoting neurological function recovery.  相似文献   
92.
93.
94.
BackgroundSecond-hand smoking or environmental tobacco smoke is a critical health risk. Children are the most vulnerable to second-hand smoking because of their small bronchial ducts, less developed immunity, and low-physical activity.ObjectivesThe purpose of this study was to ascertain the effects of second-hand smoking on lung functions in athlete and non-athlete school-aged children.MethodsThis observational study included forty-six school-aged children, their age was 8–15 years, assigned to three groups; 2 study groups and 1 control group (n=15). The study groups comprised of 16 football players, and of 15 cyclists. Lung functions were evaluated recording forced vital capacity, forced expiratory volume in 1 sec and peak expiratory flow using digital spirometer.ResultsAll measures were recorded in definite values and the children were also classified into second-hand smoking (SH), or non-exposed to tobacco smoking (NE). The findings presented a significant increase (p<0.05) of the study groups in forced vital capacity, forced expiratory volume in 1 sec and peak expiratory flow solely for the non-exposed children. However, there were non-significant differences between the cyclists and football players or between the passive smoking children and non-exposed children in any of the two study groups (p>0.05).ConclusionThe outcomes of this study suggest beneficial influences of the sports activity on the lung functions, without different influences of the cyclists and football players on the lung functions.  相似文献   
95.
96.
97.
98.
99.
As millions of people turn to social media for health information, better understanding the factors that guide health-related judgments and perceptions in this context is imperative. We report on two Web experiments (n > 400 total) examining the power of society’s widespread weight bias and related stereotypes to influence nutrition judgments in social media spaces. In Experiment 1, meals were judged as lower in nutritional quality when the person who recommended them (the source) was depicted as obese rather than of normal weight, an effect mediated by stereotypic beliefs about the source as a generally unhealthy person. Experiment 2 replicated this effect, which—notably—remained significant when controlling for objective nutritional information (calories and fat content). Results highlight spillover effects of weight bias that extend beyond person perception to color impressions of objects (here, food) that are associated with stigmatized attributes. Implications for everyday nutrition judgments and public health are considered.  相似文献   
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