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   3560866篇
  免费   310453篇
  国内免费   17807篇
耳鼻咽喉   48888篇
儿科学   109747篇
妇产科学   90687篇
基础医学   565017篇
口腔科学   98352篇
临床医学   323584篇
内科学   630158篇
皮肤病学   97461篇
神经病学   301435篇
特种医学   139182篇
外国民族医学   318篇
外科学   550928篇
综合类   112083篇
现状与发展   30篇
一般理论   2245篇
预防医学   286211篇
眼科学   83543篇
药学   255574篇
  55篇
中国医学   13838篇
肿瘤学   179790篇
  2021年   57190篇
  2020年   38842篇
  2019年   64518篇
  2018年   76608篇
  2017年   60297篇
  2016年   66323篇
  2015年   80803篇
  2014年   115174篇
  2013年   180348篇
  2012年   97024篇
  2011年   97123篇
  2010年   122305篇
  2009年   124725篇
  2008年   82220篇
  2007年   85201篇
  2006年   95594篇
  2005年   90096篇
  2004年   91157篇
  2003年   82139篇
  2002年   71651篇
  2001年   124000篇
  2000年   117255篇
  1999年   112816篇
  1998年   67521篇
  1997年   64681篇
  1996年   61867篇
  1995年   57338篇
  1994年   51130篇
  1993年   47769篇
  1992年   77450篇
  1991年   73065篇
  1990年   69729篇
  1989年   68708篇
  1988年   63005篇
  1987年   61276篇
  1986年   57982篇
  1985年   57153篇
  1984年   50734篇
  1983年   45976篇
  1982年   42147篇
  1981年   39463篇
  1980年   37344篇
  1979年   41178篇
  1978年   35452篇
  1977年   33209篇
  1976年   29596篇
  1975年   28840篇
  1974年   29360篇
  1973年   28228篇
  1972年   26499篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
32.
The coronavirus disease 2019 (COVID-19) pandemic has rapidly created widespread impacts on global health and the economy. Data suggest that women are less susceptible to severe illness. However, sex-disaggregated data are incomplete, leaving room for misinterpretation, and focusing only on biologic sex underestimates the gendered impact of the pandemic on women. This narrative review summarizes what is known about gender disparities during the COVID-19 pandemic and the economic, domestic, and health burdens along with overlapping vulnerabilities related to the pandemic. In addition, this review outlines recommended strategies that advocacy groups, community leaders, and policymakers should implement to mitigate the widening gender disparities related to COVID-19.  相似文献   
33.
34.
35.
The coronavirus 2019 pandemic has affected almost every aspect of health care delivery in the United States, and the emergency medicine system has been hit particularly hard while dealing with this public health crisis. In an unprecedented time in our history, medical systems and clinicians have been asked to be creative, flexible, and innovative, all while continuing to uphold the important standards in the US health care system. To continue providing quality services to patients during this extraordinary time, care providers, organizations, administrators, and insurers have needed to alter longstanding models and procedures to respond to the dynamics of a pandemic. The Emergency Medicine Treatment and Active Labor Act of 1986, or EMTALA, is 1 example of where these alterations have allowed health care facilities and clinicians to continue their work of caring for patients while protecting both the patients and the clinicians themselves from infectious exposures at the same time.  相似文献   
36.
Isolated patellofemoral arthritis is an increasingly recognized entity, and is usually associated with previous patellofemoral dysplasia or instability. Patellofemoral arthroplasty (PFA) has evolved significantly in recent years, both in terms of implant design and importantly in the understanding of appropriate patient selection. This review outlines the indications and investigations for PFA, provides a brief history of the development of contemporary implants, and presents the clinical outcomes for the prostheses most commonly used in the UK. In addition, it provides a detailed surgical technique for implantation of an onlay implant, with tips on how to optimize patellofemoral biomechanics and thus achieve a consistently good outcome.  相似文献   
37.
38.
39.
40.
Amacrine cells of the retina are conspicuously variable in their morphologies, their population demographics, and their ensuing functions. Vesicular glutamate transporter 3 (VGluT3) amacrine cells are a recently characterized type of amacrine cell exhibiting local dendritic autonomy. The present analysis has examined three features of this VGluT3 population, including their density, local distribution, and dendritic spread, to discern the extent to which these are interrelated, using male and female mice. We first demonstrate that Bax-mediated cell death transforms the mosaic of VGluT3 cells from a random distribution into a regular mosaic. We subsequently examine the relationship between cell density and mosaic regularity across recombinant inbred strains of mice, finding that, although both traits vary across the strains, they exhibit minimal covariation. Other genetic determinants must therefore contribute independently to final cell number and to mosaic order. Using a conditional KO approach, we further demonstrate that Bax acts via the bipolar cell population, rather than cell-intrinsically, to control VGluT3 cell number. Finally, we consider the relationship between the dendritic arbors of single VGluT3 cells and the distribution of their homotypic neighbors. Dendritic field area was found to be independent of Voronoi domain area, while dendritic coverage of single cells was not conserved, simply increasing with the size of the dendritic field. Bax-KO retinas exhibited a threefold increase in dendritic coverage. Each cell, however, contributed less dendrites at each depth within the plexus, intermingling their processes with those of neighboring cells to approximate a constant volumetric density, yielding a uniformity in process coverage across the population.SIGNIFICANCE STATEMENT Different types of retinal neuron spread their processes across the surface of the retina to achieve a degree of dendritic coverage that is characteristic of each type. Many of these types achieve a constant coverage by varying their dendritic field area inversely with the local density of like-type neighbors. Here we report a population of retinal amacrine cells that do not develop dendritic arbors in relation to the spatial positioning of such homotypic neighbors; rather, this cell type modulates the extent of its dendritic branching when faced with a variable number of overlapping dendritic fields to approximate a uniformity in dendritic density across the retina.  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