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   1716951篇
  免费   128264篇
  国内免费   3826篇
耳鼻咽喉   22041篇
儿科学   56199篇
妇产科学   46664篇
基础医学   244420篇
口腔科学   49132篇
临床医学   154220篇
内科学   338043篇
皮肤病学   38982篇
神经病学   133270篇
特种医学   64778篇
外国民族医学   242篇
外科学   261399篇
综合类   39256篇
现状与发展   5篇
一般理论   577篇
预防医学   126347篇
眼科学   40746篇
药学   125438篇
  7篇
中国医学   4517篇
肿瘤学   102758篇
  2021年   13680篇
  2019年   14284篇
  2018年   20794篇
  2017年   15855篇
  2016年   17284篇
  2015年   19715篇
  2014年   27323篇
  2013年   39276篇
  2012年   54789篇
  2011年   57565篇
  2010年   33900篇
  2009年   31718篇
  2008年   53150篇
  2007年   56399篇
  2006年   56673篇
  2005年   53883篇
  2004年   51925篇
  2003年   49172篇
  2002年   47257篇
  2001年   92036篇
  2000年   93807篇
  1999年   77141篇
  1998年   19876篇
  1997年   17376篇
  1996年   17473篇
  1995年   16823篇
  1994年   15352篇
  1993年   14133篇
  1992年   57512篇
  1991年   55375篇
  1990年   53066篇
  1989年   50832篇
  1988年   46214篇
  1987年   45030篇
  1986年   42295篇
  1985年   40085篇
  1984年   29431篇
  1983年   24981篇
  1982年   13948篇
  1979年   25587篇
  1978年   17617篇
  1977年   14942篇
  1976年   13899篇
  1975年   14583篇
  1974年   17672篇
  1973年   16973篇
  1972年   15702篇
  1971年   14479篇
  1970年   13457篇
  1969年   12534篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Molnár  B.  Aroca  S.  Dobos  A.  Orbán  K.  Szabó  J.  Windisch  P.  Stähli  A.  Sculean  A. 《Clinical oral investigations》2022,26(12):7135-7142
Clinical Oral Investigations - To evaluate t he long-term outcomes following treatment of RT 1 multiple adjacent gingival recessions (MAGR) using the modified coronally advanced tunnel (MCAT) with...  相似文献   
2.
Die Anaesthesiologie - Auch wenn für Anästhesiologen über Jahrzehnte die Prophylaxe und Therapie postoperativer Schmerzen im Rahmen des postoperativen Patientenkomforts an vorderster...  相似文献   
3.
4.
5.
6.
7.
PurposeUnderstanding the value of genetic screening and testing for monogenic disorders requires high-quality, methodologically robust economic evaluations. This systematic review sought to assess the methodological quality among such studies and examined opportunities for improvement.MethodsWe searched PubMed, Cochrane, Embase, and Web of Science for economic evaluations of genetic screening/testing (2013-2019). Methodological rigor and adherence to best practices were systematically assessed using the British Medical Journal checklist.ResultsAcross the 47 identified studies, there were substantial variations in modeling approaches, reporting detail, and sophistication. Models ranged from simple decision trees to individual-level microsimulations that compared between 2 and >20 alternative interventions. Many studies failed to report sufficient detail to enable replication or did not justify modeling assumptions, especially for costing methods and utility values. Meta-analyses, systematic reviews, or calibration were rarely used to derive parameter estimates. Nearly all studies conducted some sensitivity analysis, and more sophisticated studies implemented probabilistic sensitivity/uncertainty analysis, threshold analysis, and value of information analysis.ConclusionWe describe a heterogeneous body of work and present recommendations and exemplar studies across the methodological domains of (1) perspective, scope, and parameter selection; (2) use of uncertainty/sensitivity analyses; and (3) reporting transparency for improvement in the economic evaluation of genetic screening/testing.  相似文献   
8.
9.
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   
10.
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