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   2468337篇
  免费   187408篇
  国内免费   5528篇
耳鼻咽喉   35037篇
儿科学   78650篇
妇产科学   71574篇
基础医学   347547篇
口腔科学   71007篇
临床医学   215850篇
内科学   486738篇
皮肤病学   57219篇
神经病学   200946篇
特种医学   96121篇
外国民族医学   879篇
外科学   376198篇
综合类   57652篇
现状与发展   8篇
一般理论   863篇
预防医学   184155篇
眼科学   57711篇
药学   180129篇
  4篇
中国医学   5443篇
肿瘤学   137542篇
  2018年   25292篇
  2017年   19637篇
  2016年   21991篇
  2015年   24737篇
  2014年   35043篇
  2013年   52756篇
  2012年   70442篇
  2011年   74568篇
  2010年   44131篇
  2009年   42512篇
  2008年   70144篇
  2007年   75170篇
  2006年   76152篇
  2005年   73892篇
  2004年   71046篇
  2003年   68259篇
  2002年   66709篇
  2001年   119197篇
  2000年   122285篇
  1999年   102654篇
  1998年   28458篇
  1997年   25835篇
  1996年   25376篇
  1995年   24068篇
  1994年   22178篇
  1993年   20703篇
  1992年   78668篇
  1991年   75598篇
  1990年   73424篇
  1989年   70867篇
  1988年   65627篇
  1987年   64238篇
  1986年   61104篇
  1985年   57978篇
  1984年   43957篇
  1983年   37194篇
  1982年   22557篇
  1981年   20337篇
  1979年   40530篇
  1978年   28790篇
  1977年   24577篇
  1976年   22554篇
  1975年   24656篇
  1974年   29292篇
  1973年   28518篇
  1972年   27047篇
  1971年   24910篇
  1970年   23755篇
  1969年   22529篇
  1968年   21260篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
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   
73.
74.

Researchers have highlighted numerous sociocultural factors that have been shown to underpin human appearance enhancement practices, including the influence of peers, family, the media, and sexual objectification. Fewer scholars have approached appearance enhancement from an evolutionary perspective or considered how sociocultural factors interact with evolved psychology to produce appearance enhancement behavior. Following others, we argue that evidence from the field of evolutionary psychology can complement existing sociocultural models by yielding unique insight into the historical and cross-cultural ubiquity of competition over aspects of physical appearance to embody what is desired by potential mates. An evolutionary lens can help to make sense of reliable sex and individual differences that impact appearance enhancement, as well as the context-dependent nature of putative adaptations that function to increase physical attractiveness. In the current review, appearance enhancement is described as a self-promotion strategy used to enhance reproductive success by rendering oneself more attractive than rivals to mates, thereby increasing one’s mate value. The varied ways in which humans enhance their appearance are described, as well as the divergent tactics used by women and men to augment their appearance, which correspond to the preferences of opposite-sex mates in a heterosexual context. Evolutionarily relevant individual differences and contextual factors that vary predictably with appearance enhancement behavior are also discussed. The complementarity of sociocultural and evolutionary perspectives is emphasized and recommended avenues for future interdisciplinary research are provided for scholars interested in studying appearance enhancement behavior.

  相似文献   
75.
76.
77.
78.
79.
80.
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