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   3767065篇
  免费   311277篇
  国内免费   14646篇
耳鼻咽喉   50678篇
儿科学   119362篇
妇产科学   97623篇
基础医学   590530篇
口腔科学   102192篇
临床医学   339949篇
内科学   673377篇
皮肤病学   98473篇
神经病学   316838篇
特种医学   146876篇
外国民族医学   262篇
外科学   580889篇
综合类   113882篇
现状与发展   23篇
一般理论   2355篇
预防医学   310641篇
眼科学   88919篇
药学   260836篇
  26篇
中国医学   11408篇
肿瘤学   187849篇
  2021年   55619篇
  2020年   35405篇
  2019年   58510篇
  2018年   72746篇
  2017年   55515篇
  2016年   61378篇
  2015年   75140篇
  2014年   109344篇
  2013年   174785篇
  2012年   104370篇
  2011年   106245篇
  2010年   120738篇
  2009年   123678篇
  2008年   92818篇
  2007年   97366篇
  2006年   106886篇
  2005年   101653篇
  2004年   103379篇
  2003年   93302篇
  2002年   82679篇
  2001年   136124篇
  2000年   129667篇
  1999年   122043篇
  1998年   68614篇
  1997年   65278篇
  1996年   63009篇
  1995年   58557篇
  1994年   52536篇
  1993年   48902篇
  1992年   85077篇
  1991年   80997篇
  1990年   76722篇
  1989年   75172篇
  1988年   69071篇
  1987年   67234篇
  1986年   63558篇
  1985年   62796篇
  1984年   54914篇
  1983年   49589篇
  1982年   43621篇
  1981年   40989篇
  1980年   38457篇
  1979年   44860篇
  1978年   38246篇
  1977年   34936篇
  1976年   31971篇
  1975年   30793篇
  1974年   32486篇
  1973年   31189篇
  1972年   29041篇
排序方式: 共有10000条查询结果,搜索用时 15 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