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   87529篇
  免费   6996篇
  国内免费   4213篇
耳鼻咽喉   1181篇
儿科学   1055篇
妇产科学   840篇
基础医学   9429篇
口腔科学   1539篇
临床医学   8858篇
内科学   12587篇
皮肤病学   1345篇
神经病学   4136篇
特种医学   4302篇
外国民族医学   8篇
外科学   11537篇
综合类   14401篇
现状与发展   15篇
一般理论   16篇
预防医学   6298篇
眼科学   1959篇
药学   8486篇
  57篇
中国医学   4301篇
肿瘤学   6388篇
  2024年   178篇
  2023年   864篇
  2022年   2161篇
  2021年   3241篇
  2020年   2406篇
  2019年   2187篇
  2018年   2452篇
  2017年   2347篇
  2016年   2461篇
  2015年   3680篇
  2014年   4674篇
  2013年   5177篇
  2012年   7620篇
  2011年   7750篇
  2010年   5802篇
  2009年   5017篇
  2008年   5834篇
  2007年   5638篇
  2006年   5294篇
  2005年   4563篇
  2004年   3563篇
  2003年   3386篇
  2002年   2942篇
  2001年   2242篇
  2000年   1617篇
  1999年   1092篇
  1998年   519篇
  1997年   512篇
  1996年   367篇
  1995年   304篇
  1994年   260篇
  1993年   170篇
  1992年   255篇
  1991年   275篇
  1990年   207篇
  1989年   192篇
  1988年   168篇
  1987年   182篇
  1986年   144篇
  1985年   128篇
  1984年   87篇
  1983年   87篇
  1982年   52篇
  1979年   72篇
  1978年   43篇
  1977年   46篇
  1975年   46篇
  1974年   46篇
  1973年   44篇
  1969年   45篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
Abstract

Background

Comorbidities are commonly seen in patients with coronavirus disease 2019 (COVID-19), but the clinical implication is not yet well-delineated. We aim to characterize the prevalence and clinical implications of comorbidities in patients with COVID-19.  相似文献   
3.
4.
5.
6.
7.
Membrane trafficking processes are presumably vital for axonal regeneration after injury, but mechanistic understanding in this regard has been sparse. A recent loss-of-function screen had been carried out for factors important for axonal regeneration by cultured cortical neurons and the results suggested that the activity of a number of Rab GTPases might act to restrict axonal regeneration. A loss of Rab27b, in particular, is shown to enhance axonal regeneration in vitro, as well as in C. elegans and mouse central nervous system injury models in vivo. Possible mechanisms underlying this new finding, which has important academic and translational implication, are discussed.  相似文献   
8.
9.
Objective Ligustrazine, also named as tetramethylpyrazine, is a compound purified from Ligusticum chuanxiong hort and has ever been testified to be a calcium antagonist. The present investigation was to determine the antinoci-ceptive effect of ligustrazine and, if any, the peripheral ionic mechanism involved. Methods Paw withdrawal Latency ( PWL) to noxious heating was measured in vivo and whole-cell patch recording was performed on small dorsal root ganglion (DRG) neurons. Results Intraplantar injection of ligustrazine (0.5 mg in 25μl) significantly prolonged the withdrawal latency of ipsilateral hindpaw to noxious heating in the rat. Ligustrazine not only reversibly inhibited high-voltage gated calcium current of dorsal root ganglion (DRG) neuron in dose-dependent manner with IC50 of 1.89 mmol/L, but also decreased tetrodotoxin (TTX) -resistant sodium current in relatively selective and dose-dependent manner with IC50 of 2.49 mmol/L. Conclusion The results suggested that ligustrazine could elevate the threshold of thermal nociception through inhibiting the high-voltage gated calcium current and TTX-resistant sodium current of DRG neuron in the rat.  相似文献   
10.
Levels of the soluble form of the triggering receptor expressed on myeloid cells (sTREM)-1 are elevated in severe sepsis. However, it is not known whether sTREM-1 measurements can distinguish milder bacterial infections from noninfectious inflammation. The present authors studied whether serum sTREM-1 levels differ in community-acquired pneumonia, exacerbations of chronic obstructive pulmonary disease (COPD), asthma and controls, and whether sTREM-1 may be used as a surrogate marker for the need for antibiotics. Serum sTREM-1 levels in 150 patients with pneumonia, COPD and asthma exacerbations and 62 healthy controls were measured. Serum sTREM-1 levels were significantly elevated in pneumonia (median 295.2 ng x mL(-1)), COPD (280.3 ng x mL(-1)) and asthma exacerbations (184.0 ng x mL(-1)) compared with controls (83.1 ng x mL(-1)). Levels were higher in pneumonia and Anthonisen type 1 COPD exacerbations than in type 2 and 3 COPD and asthma exacerbations. The area under the receiver operating characteristics curve for sTREM-1 as a surrogate marker for the need for antibiotics was 0.77. Serum levels of the soluble form of the triggering receptor expressed on myeloid cells-1 were elevated predominantly in pneumonia and Anthonisen type 1 COPD exacerbations versus type 2 and 3 chronic obstructive pulmonary disease exacerbations, asthma and controls. Serum levels of the soluble form of the triggering receptor expressed on myeloid cells-1 has moderate but insufficient accuracy as a surrogate marker for the need for antibiotics in lower respiratory tract infections.  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