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   5436747篇
  免费   416748篇
  国内免费   16330篇
耳鼻咽喉   76509篇
儿科学   175479篇
妇产科学   147598篇
基础医学   804865篇
口腔科学   153427篇
临床医学   506024篇
内科学   993736篇
皮肤病学   127909篇
神经病学   450542篇
特种医学   210140篇
外国民族医学   1332篇
外科学   807526篇
综合类   152626篇
现状与发展   25篇
一般理论   3112篇
预防医学   456668篇
眼科学   129671篇
药学   387665篇
  28篇
中国医学   14251篇
肿瘤学   270692篇
  2021年   57396篇
  2019年   59710篇
  2018年   77642篇
  2017年   59745篇
  2016年   66197篇
  2015年   78119篇
  2014年   112623篇
  2013年   178448篇
  2012年   157472篇
  2011年   168691篇
  2010年   135965篇
  2009年   134245篇
  2008年   153550篇
  2007年   165816篇
  2006年   171715篇
  2005年   166181篇
  2004年   166009篇
  2003年   155244篇
  2002年   143989篇
  2001年   218040篇
  2000年   215700篇
  1999年   191603篇
  1998年   78241篇
  1997年   72282篇
  1996年   70336篇
  1995年   65742篇
  1994年   59731篇
  1993年   55260篇
  1992年   142092篇
  1991年   136860篇
  1990年   132173篇
  1989年   128388篇
  1988年   118570篇
  1987年   116313篇
  1986年   109877篇
  1985年   106719篇
  1984年   85681篇
  1983年   75209篇
  1982年   54364篇
  1981年   50101篇
  1980年   46978篇
  1979年   76149篇
  1978年   58908篇
  1977年   51321篇
  1976年   47732篇
  1975年   49169篇
  1974年   55992篇
  1973年   54121篇
  1972年   51082篇
  1971年   47434篇
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
31.
32.
33.
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   
34.
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   
35.
36.
37.
38.
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   
39.
BackgroundTotal hip and knee arthroplasties are increasingly performed operations, and routine follow-up places huge demands on orthopedic services. This study investigates the effectiveness, patients’ satisfaction, and cost reduction of Virtual Joint Replacement Clinic (VJRC) follow-up of total hip arthroplasty and total knee arthroplasty patients in a university hospital. VJRC is especially valuable when in-person appointments are not advised or feasible such as during the COVID-19 pandemic.MethodsA total of 1749 patients who were invited for VJRC follow-up for knee or hip arthroplasty from January 2017 to December 2018 were included in this retrospective study. Patients were referred to VJRC after their 6-week postoperative review. Routine VJRC postoperative review was undertaken at 1 and 7 years and then 3-yearly thereafter. We evaluated the VJRC patient response rate, acceptability, and outcome. Patient satisfaction was measured in a subgroup of patients using a satisfaction survey. VJRC costs were calculated compared to face-to-face follow-up.ResultsThe VJRC had a 92.05% overall response rate. Only 7.22% required further in-person appointments with only 3% being reviewed by an orthopedic consultant. VJRC resulted in an estimated saving of £42,644 per year at our institution. The patients’ satisfaction survey showed that 89.29% of the patients were either satisfied or very satisfied with VJRC follow-up.ConclusionVJRC follow-up for hip and knee arthroplasty patients is an effective alternative to in-person clinic assessment which is accepted by patients, has high patient satisfaction, and can reduce the cost to both health services and patients.  相似文献   
40.
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