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   3226197篇
  免费   262268篇
  国内免费   6644篇
耳鼻咽喉   46014篇
儿科学   102147篇
妇产科学   89171篇
基础医学   452719篇
口腔科学   92507篇
临床医学   295324篇
内科学   630973篇
皮肤病学   69048篇
神经病学   271878篇
特种医学   126985篇
外国民族医学   1186篇
外科学   484823篇
综合类   78390篇
现状与发展   4篇
一般理论   1333篇
预防医学   262302篇
眼科学   76436篇
药学   236566篇
  5篇
中国医学   6556篇
肿瘤学   170742篇
  2018年   34610篇
  2017年   26563篇
  2016年   29500篇
  2015年   33343篇
  2014年   48000篇
  2013年   72715篇
  2012年   98064篇
  2011年   103678篇
  2010年   61169篇
  2009年   58536篇
  2008年   97433篇
  2007年   103403篇
  2006年   104412篇
  2005年   101587篇
  2004年   97450篇
  2003年   93769篇
  2002年   91748篇
  2001年   150892篇
  2000年   155602篇
  1999年   131054篇
  1998年   38419篇
  1997年   34818篇
  1996年   34473篇
  1995年   33048篇
  1994年   30745篇
  1993年   28810篇
  1992年   103582篇
  1991年   99584篇
  1990年   95901篇
  1989年   92208篇
  1988年   85518篇
  1987年   84100篇
  1986年   79282篇
  1985年   75753篇
  1984年   57821篇
  1983年   49266篇
  1982年   30185篇
  1981年   26850篇
  1979年   53502篇
  1978年   37772篇
  1977年   31665篇
  1976年   29775篇
  1975年   31025篇
  1974年   38147篇
  1973年   36454篇
  1972年   34205篇
  1971年   31460篇
  1970年   29737篇
  1969年   27656篇
  1968年   25602篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
Behçet disease is a complex, multisystem disease characterized by recurrent oral and genital ulcerations. It rarely occurs in infants or children. Neonatal Behçet disease has been reported in infants whose ulcers resolve at or before 9 weeks of age. Few cases of neonatal Behçet disease persisting into childhood have previously been reported. We report the case of a 1‐month‐old infant who presented with severe recurrent genital ulcerations and at 6 months developed recurrent oral ulcerations. Her orogenital ulcerations continue to recur. Human leukocyte antigen testing revealed HLA‐B51 and B44 positivity. This is a case of pediatric Behçet disease in the neonatal period. Behçet disease should be considered in the differential diagnosis of recurrent genital and oral ulcerations in infants and children.  相似文献   
104.
105.
Caring for patients with end-stage kidney disease (ESKD) in the United States is challenging, due in part to the complex epidemiology of the disease's progression as well as the ways in which care is delivered. As CKD progresses toward ESKD, the number of comorbidities increases and care involves multiple healthcare providers from multiple subspecialties. This occurs in the context of a fragmented US healthcare delivery system that is traditionally siloed by provider specialty, organization, as well as systems of payment and administration. This article describes the role of care fragmentation in the delivery of optimal ESKD care and identifies research gaps in the evidence across the continuum of care. We then consider the impact of care fragmentation on ESKD care from the patient and health system perspectives and explore opportunities for system-level interventions aimed at improving care for patients with ESKD.  相似文献   
106.
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   
107.
108.

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   
109.
110.
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