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   1546961篇
  免费   121848篇
  国内免费   3777篇
耳鼻咽喉   20302篇
儿科学   50536篇
妇产科学   44413篇
基础医学   219450篇
口腔科学   42126篇
临床医学   135106篇
内科学   317787篇
皮肤病学   37286篇
神经病学   128417篇
特种医学   57521篇
外国民族医学   468篇
外科学   227330篇
综合类   33554篇
现状与发展   3篇
一般理论   528篇
预防医学   123979篇
眼科学   34363篇
药学   108366篇
  1篇
中国医学   3968篇
肿瘤学   87082篇
  2021年   14225篇
  2019年   14932篇
  2018年   22842篇
  2017年   16364篇
  2016年   17211篇
  2015年   19172篇
  2014年   26563篇
  2013年   39261篇
  2012年   55113篇
  2011年   58168篇
  2010年   33605篇
  2009年   31225篇
  2008年   52631篇
  2007年   55553篇
  2006年   55476篇
  2005年   53893篇
  2004年   51070篇
  2003年   48560篇
  2002年   46703篇
  2001年   76175篇
  2000年   78234篇
  1999年   64368篇
  1998年   17753篇
  1997年   15918篇
  1996年   16071篇
  1995年   15182篇
  1994年   13707篇
  1993年   12888篇
  1992年   47045篇
  1991年   44481篇
  1990年   42500篇
  1989年   40402篇
  1988年   36907篇
  1987年   36099篇
  1986年   33595篇
  1985年   31912篇
  1984年   24296篇
  1983年   20400篇
  1982年   12420篇
  1981年   10966篇
  1979年   21132篇
  1978年   14880篇
  1977年   12367篇
  1976年   11640篇
  1975年   11948篇
  1974年   14360篇
  1973年   13963篇
  1972年   13014篇
  1971年   11853篇
  1970年   11262篇
排序方式: 共有10000条查询结果,搜索用时 812 毫秒
1.
2.
3.

The exercise pressor reflex is a feedback mechanism engaged upon stimulation of mechano- and metabosensitive skeletal muscle afferents. Activation of these afferents elicits a reflex increase in heart rate, blood pressure, and ventilation in an intensity-dependent manner. Consequently, the exercise pressor reflex has been postulated to be one of the principal mediators of the cardiorespiratory responses to exercise. In this updated review, we will discuss classical and recent advancements in our understating of the exercise pressor reflex function in both human and animal models. Particular attention will be paid to the afferent mechanisms and pathways involved during its activation, its effects on different target organs, its potential role in the abnormal cardiovascular response to exercise in diseased states, and the impact of age and biological sex on these responses. Finally, we will highlight some unanswered questions in the literature that may inspire future investigations in the field.

  相似文献   
4.
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   
5.
6.
7.
International Journal of Clinical Oncology - Immune-checkpoint inhibitors (ICIs) are standard treatments for metastatic non-small cell lung cancer (NSCLC). Patients with poor performance status...  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