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   3580427篇
  免费   288903篇
  国内免费   14215篇
耳鼻咽喉   49595篇
儿科学   114150篇
妇产科学   93222篇
基础医学   561766篇
口腔科学   96269篇
临床医学   318489篇
内科学   636332篇
皮肤病学   93008篇
神经病学   304116篇
特种医学   140625篇
外国民族医学   404篇
外科学   557256篇
综合类   104772篇
现状与发展   25篇
一般理论   2426篇
预防医学   300592篇
眼科学   81949篇
药学   248696篇
  24篇
中国医学   10042篇
肿瘤学   169787篇
  2021年   55889篇
  2020年   35632篇
  2019年   58848篇
  2018年   72679篇
  2017年   55404篇
  2016年   61114篇
  2015年   75255篇
  2014年   109888篇
  2013年   175764篇
  2012年   100216篇
  2011年   102108篇
  2010年   119911篇
  2009年   123554篇
  2008年   89769篇
  2007年   94440篇
  2006年   104455篇
  2005年   100722篇
  2004年   102111篇
  2003年   92871篇
  2002年   82878篇
  2001年   105272篇
  2000年   97928篇
  1999年   98143篇
  1998年   66012篇
  1997年   63498篇
  1996年   61431篇
  1995年   56798篇
  1994年   51099篇
  1993年   47466篇
  1992年   70034篇
  1991年   67234篇
  1990年   64628篇
  1989年   63734篇
  1988年   59670篇
  1987年   58161篇
  1986年   55453篇
  1985年   55463篇
  1984年   50004篇
  1983年   46049篇
  1982年   42449篇
  1981年   39893篇
  1980年   37613篇
  1979年   42029篇
  1978年   36675篇
  1977年   33617篇
  1976年   30945篇
  1975年   30207篇
  1974年   31434篇
  1973年   30220篇
  1972年   28461篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
ContextIt is especially important that patients are well informed when making high-stakes, preference-sensitive decisions like those on the Physician Orders for Life-Sustaining Treatment (POLST) form. However, there is currently no way to easily evaluate whether patients understand key concepts when making these important decisions.ObjectivesTo develop a POLST knowledge survey.MethodsExpert (n = 62) ratings of key POLST facts were used to select items for a POLST knowledge survey. The survey was administered to nursing facility residents (n = 97) and surrogate decision-makers (n = 112). A subset (n = 135) were re-administered the survey after a standardized advance care planning discussion to assess the scale's responsiveness to change.ResultsThe 19-item survey demonstrated adequate reliability (α = 0.72.). Residents' scores (x = 11.4, standard deviation 3.3) were significantly lower than surrogate scores (x = 14.7, standard deviation 2.5) (P < 0.001). Scores for both groups increased significantly after administration of a standardized advance care planning discussion (P < 0.001). Although being a surrogate, age, race, education, cognitive functioning, and health literacy were significantly associated with higher POLST Knowledge Survey scores in univariate analyses, only being a surrogate (P < 0.001) and being white (P = 0.028) remained significantly associated with higher scores in multivariate analyses.ConclusionThe 19-item POLST Knowledge Survey demonstrated adequate reliability and responsiveness to change. Findings suggest the survey could be used to identify knowledge deficits and provide targeted education to ensure adequate understanding of key clinical decisions when completing POLST.  相似文献   
82.
83.
84.
85.
Pharmaceutical Chemistry Journal - Three extracts were produced from the above-ground part of the meadowsweet Filipendula ulmaria (L.) Maxim. using water, 40% ethanol, and 70% ethanol. Comparative...  相似文献   
86.
87.
88.
89.
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   
90.
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   
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