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   6503篇
  免费   564篇
  国内免费   228篇
耳鼻咽喉   95篇
儿科学   87篇
妇产科学   83篇
基础医学   743篇
口腔科学   208篇
临床医学   625篇
内科学   1168篇
皮肤病学   103篇
神经病学   381篇
特种医学   287篇
外国民族医学   1篇
外科学   948篇
综合类   689篇
现状与发展   3篇
一般理论   3篇
预防医学   388篇
眼科学   169篇
药学   621篇
  1篇
中国医学   309篇
肿瘤学   383篇
  2024年   13篇
  2023年   94篇
  2022年   222篇
  2021年   266篇
  2020年   184篇
  2019年   221篇
  2018年   229篇
  2017年   178篇
  2016年   177篇
  2015年   236篇
  2014年   315篇
  2013年   321篇
  2012年   498篇
  2011年   508篇
  2010年   289篇
  2009年   225篇
  2008年   323篇
  2007年   344篇
  2006年   293篇
  2005年   305篇
  2004年   232篇
  2003年   212篇
  2002年   186篇
  2001年   158篇
  2000年   163篇
  1999年   138篇
  1998年   75篇
  1997年   79篇
  1996年   50篇
  1995年   57篇
  1994年   39篇
  1993年   47篇
  1992年   86篇
  1991年   70篇
  1990年   60篇
  1989年   57篇
  1988年   49篇
  1987年   46篇
  1986年   36篇
  1985年   25篇
  1984年   16篇
  1983年   12篇
  1980年   13篇
  1979年   12篇
  1978年   14篇
  1977年   20篇
  1976年   10篇
  1974年   14篇
  1973年   15篇
  1972年   14篇
排序方式: 共有7295条查询结果,搜索用时 0 毫秒
21.
22.
23.
Wu WC  Wang Y  Su CK  Chai CY 《Neuroscience letters》2001,302(2-3):121-124
The potential neuroprotective effects of the novel nitro-derivate of aspirin (NCX4016) on permanent focal cerebral ischemia in spontaneously hypertensive rats (SHRs) was investigated. Reference compounds were acetylsalicilic acid (ASA) and FK506 (tacrolimus). Ten minutes after surgery, SHRs were randomly divided into four groups of ten, pharmacologically treated and sacrificed 24 h after treatment. Brains were removed and processed to measure infarct volume, 70 kDa heat shock protein (hsp70), glial fibrillary acidic protein (GFAP) and vimentin (Vim) immunoreactivity (IR), and apoptosis using terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-digoxigenin nick end-labeling (TUNEL) assay. NCX-4016 significantly reduced total infarct volume compared to ASA (-20%, P < 0.05), FK506 (-18%, P < 0.05) and vehicle treatment (-20%, P < 0.05). Experimental groups did not differ in hsp70-IR and GFAP-IR. Conversely, hyperplastic astrocytes, measured by Vim-IR, were significantly lower in NCX-4016 than in the vehicle group (-36%, P<0.01). TUNEL assay indicated a significantly lower degree of apoptosis in NCX-4016 group than vehicle in both the homolateral (-27%, P < 0.01) and contralateral hemisphere (-29%, P < 0.05). These findings indicate that NO release associated with aspirin confers neuroprotective effects against ischemic injury.  相似文献   
24.
25.
Decreased plasma levels of apolipoprotein A-I (apo A-I) and increased plasma levels of apolipoprotein B (apo B) have been shown to correlate with increased risk of atherosclerosis. While many studies have investigated the plasma levels of these apolipoproteins with regard to their value as predictors of cardiovascular disease, comparatively little is known about their precise tissue localization in atherosclerotic plaques. The purpose of this study was to determine the tissue localization of apo A-I and apo B in atherosclerotic segments of human carotid arteries through the use of immunohistochemical techniques. With tissue samples obtained from surgery and autopsy, apo A-I and apo B were found to be present in atherosclerotic plaques and absent in normal arterial tissue. In the plaques, both apo A-I and apo B were found extracellularly, primarily in the lipid core, but also in connective tissue. In addition, both apo A-I and apo B were found intracellularly in foam cells. This similar intracellular and extracellular distribution of apo A-I and apo B was unexpected, in view of their differing associations with atherosclerosis.  相似文献   
26.
包虫病是流行于我国西部地区的一种严重的人畜共患寄生虫病。全国有22个省、市和自治区有本病发生,垒1990年底止仅西部6个省  相似文献   
27.
We conducted a systematic review and meta-analysis to assess the outcomes and complications of naftopidil in treating elderly men with lower urinary tract symptoms secondary to benign prostatic hyperplasia and compared them with those administered with tamsulosin. A literature review was performed to identify the available randomised controlled trials concerning the comparison between naftopidil and tamsulosin for men with LUTS/BPH. We searched the following databases: the Cochrane Library Database, PubMed, Embase and Web of Science. Eleven publications involving 1,114 men (557 in the naf group and 557 in the tam group) were pooled in our analysis. We found no significant differences in the total IPSS, IPSS storage score, IPSS voiding score, quality of life index, peak urinary flow rate, average flow rate and post-void residual volumes. We assessed cardiovascular and sexual adverse events, acute urinary retention, surgical intervention, withdrawals due to any reason and withdrawals due to adverse events. The incidence of adverse events was similar among patients in naf and tam groups. In conclusion, naftopidil shared comparable efficacy and similar incidence of adverse events with tamsulosin and appears to be a promising agent for and alternative to tam. However, more prospective trials with high quality and long-term treatment duration are needed to verify this observation.  相似文献   
28.
One of the hallmark characteristics of chronic diabetic wounds is the presence of biofilm‐forming bacteria. Bacteria encapsulated in a biofilm may coexist as a polymicrobial community and communicate with each other through a phenomenon termed quorum sensing (QS). Here, we describe the QS circuits of bacterial species commonly found in chronic diabetic wounds. QS relies on diffusion of signaling molecules and the local concentration changes of these molecules that bacteria experience in wounds. These biochemical signaling pathways play a role not only in biofilm formation and virulence but also in wound healing. They are, therefore, key to understanding the distinctive nature of these infections. While several in vivo and in vitro models exist to study QS in wounds, there has been limited progress in understanding the interplay between QS molecules and host factors that contribute to wound healing. Lastly, we examine the potential of targeting QS for both diagnosis and therapeutic intervention purposes.  相似文献   
29.
In this work, a novel and simple phase-field-based lattice Boltzmann (LB) method is proposed for the axisymmetric two-phase electro-hydrodynamic flows. The present LB method is composed of three LB models, which are used to solve the axisymmetric Allen-Cahn equation for the phase field, the axisymmetric Poisson equation for the electric potential, and the axisymmetric Navier-Stokes equations for the flow field. Compared with the previous LB models for the axisymmetric Poisson equation, which can be viewed as the solvers to the convection-diffusion equation, the present model is a genuine solver to the axisymmetric Poisson equation. To test the capacity of the LB method, the deformation of a single leaky or perfect dielectric drop under a uniform electric field is considered, and the effects of electric strength, conductivity ratio, and permittivity ratio are investigated in detail. It is found that the present numerical results are in good agreement with some available theoretical, numerical and/or experimental data.  相似文献   
30.
以轻质烷烃异构化中试放大用的丝光沸石催化剂为研究对象,运用“原位”红外反应技术和催化剂活性评价手段,并结合反应动力学参数计算,探讨了正已烷异构化反应机理。结果表明,可用五配位反应中间物种机理解释正碳离子的生成。用双分子六元环反应中间物机理能较好地解释正已烷在氢型丝光沸石(HM)上的异构化过程。对正已烷在Pd/HM上的反应过程也可用正碳离子机理结合双分子六元环中间物机理解释。  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