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   3621003篇
  免费   274562篇
  国内免费   24044篇
耳鼻咽喉   48104篇
儿科学   115056篇
妇产科学   98278篇
基础医学   504718篇
口腔科学   98039篇
临床医学   343030篇
内科学   700638篇
皮肤病学   83260篇
神经病学   292922篇
特种医学   138253篇
外国民族医学   1249篇
外科学   531085篇
综合类   108318篇
现状与发展   62篇
一般理论   1351篇
预防医学   278976篇
眼科学   83669篇
药学   269161篇
  200篇
中国医学   19403篇
肿瘤学   203837篇
  2021年   37340篇
  2019年   34530篇
  2018年   45948篇
  2017年   36151篇
  2016年   40089篇
  2015年   47826篇
  2014年   65022篇
  2013年   89830篇
  2012年   121462篇
  2011年   129822篇
  2010年   77636篇
  2009年   72321篇
  2008年   115305篇
  2007年   121668篇
  2006年   123733篇
  2005年   119615篇
  2004年   110964篇
  2003年   106935篇
  2002年   102476篇
  2001年   168933篇
  2000年   173488篇
  1999年   147153篇
  1998年   44436篇
  1997年   39930篇
  1996年   39350篇
  1995年   37954篇
  1994年   34422篇
  1993年   31601篇
  1992年   111401篇
  1991年   106825篇
  1990年   103292篇
  1989年   99357篇
  1988年   91164篇
  1987年   89198篇
  1986年   83491篇
  1985年   79776篇
  1984年   59763篇
  1983年   50626篇
  1982年   30268篇
  1979年   52703篇
  1978年   37271篇
  1977年   31409篇
  1976年   29257篇
  1975年   30851篇
  1974年   36738篇
  1973年   35112篇
  1972年   32996篇
  1971年   30519篇
  1970年   28354篇
  1969年   27004篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
31.
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   
32.
33.
34.
35.
Abstract

Purpose

Financial hardship can be a major cause of distress among persons with cancer, resulting in chronic stress and impacting physical and emotional health. This paper provides an analysis of the lived experience of cancer patients’ financial hardship from diagnosis to post-treatment.  相似文献   
36.
37.
“三全育人”是高校思政教育工作的关键一环,也是中医药高校推动思政教育的重要内容。以“三全育人”为视角对北京中医药大学思想政治教育举措“杏林成长导师”计划路径、内容深入分析,运用统计分析和文献研究方法,剖析该计划对中医学专业大学生的学业、思想和实践等多个层面的现实成效,从而为“三全育人”理念在中医药院校制度建构中的应用提供新的视角与方法。  相似文献   
38.
39.
Major depressive disorder and other neuropsychiatric disorders are often managed with long-term use of antidepressant medication. Fluoxetine, an SSRI antidepressant, is widely used as a first-line treatment for neuropsychiatric disorders. However, fluoxetine has also been shown to increase the risk of metabolic diseases such as non-alcoholic fatty liver disease. Fluoxetine has been shown to increase hepatic lipid accumulation in vivo and in vitro. In addition, fluoxetine has been shown to alter the production of prostaglandins which have also been implicated in the development of non-alcoholic fatty liver disease. The goal of this study was to assess the effect of fluoxetine exposure on the prostaglandin biosynthetic pathway and lipid accumulation in a hepatic cell line (H4-II-E-C3 cells). Fluoxetine treatment increased mRNA expression of prostaglandin biosynthetic enzymes (Ptgs1, Ptgs2, and Ptgds), PPAR gamma (Pparg), and PPAR gamma downstream targets involved in fatty acid uptake (Cd36, Fatp2, and Fatp5) as well as production of 15-deoxy-Δ12,14PGJ2 a PPAR gamma ligand. The effects of fluoxetine to induce lipid accumulation were attenuated with a PTGS1 specific inhibitor (SC-560), whereas inhibition of PTGS2 had no effect. Moreover, SC-560 attenuated 15-deoxy-Δ12,14PGJ2 production and expression of PPAR gamma downstream target genes. Taken together these results suggest that fluoxetine-induced lipid abnormalities appear to be mediated via PTGS1 and its downstream product 15d-PGJ2 and suggest a novel therapeutic target to prevent some of the adverse effects of fluoxetine treatment.  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