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   1988361篇
  免费   135588篇
  国内免费   4662篇
耳鼻咽喉   28292篇
儿科学   62483篇
妇产科学   54956篇
基础医学   282700篇
口腔科学   54405篇
临床医学   172799篇
内科学   386836篇
皮肤病学   44789篇
神经病学   153888篇
特种医学   80612篇
外国民族医学   535篇
外科学   303469篇
综合类   40042篇
现状与发展   6篇
一般理论   570篇
预防医学   140517篇
眼科学   46098篇
药学   152840篇
  7篇
中国医学   5756篇
肿瘤学   117011篇
  2021年   17010篇
  2019年   16450篇
  2018年   22813篇
  2017年   17787篇
  2016年   20326篇
  2015年   23664篇
  2014年   32067篇
  2013年   46390篇
  2012年   63761篇
  2011年   66645篇
  2010年   39902篇
  2009年   36921篇
  2008年   60770篇
  2007年   64094篇
  2006年   64138篇
  2005年   61761篇
  2004年   58670篇
  2003年   55997篇
  2002年   53961篇
  2001年   95982篇
  2000年   98460篇
  1999年   82900篇
  1998年   22105篇
  1997年   19674篇
  1996年   19625篇
  1995年   18250篇
  1994年   16949篇
  1993年   15967篇
  1992年   62610篇
  1991年   60068篇
  1990年   58872篇
  1989年   56645篇
  1988年   51764篇
  1987年   50588篇
  1986年   47987篇
  1985年   45463篇
  1984年   33333篇
  1983年   28203篇
  1982年   16231篇
  1979年   30241篇
  1978年   20657篇
  1977年   18174篇
  1976年   16332篇
  1975年   18265篇
  1974年   21538篇
  1973年   20680篇
  1972年   19707篇
  1971年   18309篇
  1970年   17218篇
  1969年   16433篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
132.
BackgroundGeneric antidepressants are approved on the market based on evidence of bioequivalence to their brand-name versions. We aimed to assess whether generic antidepressants exert equal effectiveness as their brand-name counterparts for treating patients with depressive disorders.MethodsIn a nationwide, population-based cohort in Taiwan from 1997 through 2013, patients with a diagnosis of a depressive disorder aged between 18 and 65 years who were new users of antidepressant drugs were classified into either the brand-name group or the generic group. All patients were followed up until medication discontinuation or the end of the study period. We assessed the risk for hospitalization as a primary outcome and augmentation therapy, daily dose, medication discontinuation, or switching to another antidepressant as secondary outcomes.ResultsA total of 277 651 brand-name users (35.8% male; mean age: 41.2 years) and 270 583 generic users (35.8% male; mean age: 41.0 years) were divided into 10 different antidepressant groups (fluoxetine, sertraline, paroxetine, escitalopram, citalopram, venlafaxine, mirtazapine, moclobemide, imipramine, and bupropion). We found that patients treated with the generic form of sertraline, paroxetine, escitalopram, venlafaxine, mirtazapine, and bupropion demonstrated significantly higher risks of psychiatric hospitalization (adjusted hazard ratios ranged from 1.20–2.34), compared to their brand-name counterparts. The differences between brand-name antidepressants and their generic counterparts in secondary outcomes varied across different drugs.ConclusionsCompared to most generic antidepressants, brand-name drugs exhibited more protective effects on psychiatric hospitalization for depressive patients. These findings could serve as an important reference for clinicians when encountering patients with depressive disorder.  相似文献   
133.
134.
135.
136.
137.
The aim of the present study was to evaluate the antimicrobial activity of two synbiotic combinations, Lactobacillus fermentum with short-chain fructooligosaccharides (FOS-LF) and Bifidobacterium longum with isomaltooligosaccharides (IMO-BL), against enterohaemorrhagic Escherichia coli O157:H7 and enteropathogenic E. coli O86. Antimicrobial activity was determined (1) by co-culturing the synbiotics and pathogens in batch cultures, and (2) with the three-stage continuous culture system (gut model), inoculated with faecal slurry from an elderly donor. In the co-culture experiments, IMO-BL was significantly inhibitory to both E. coli strains, while FOS-LF was slightly inhibitory or not inhibitory. Factors other than acid production appeared to play a role in the inhibition. In the gut models, both synbiotics effectively inhibited E. coli O157 in the first vessel, but not in vessels 2 and 3. E. coli O86 was not significantly inhibited.  相似文献   
138.
Farnesyltransferase (FTase) is one of the prenyltransferase family enzymes that catalyse the transfer of 15-membered isoprenoid (farnesyl) moiety to the cysteine of CAAX motif-containing proteins including Rho and Ras family of G proteins. Inhibitors of FTase act as drugs for cancer, malaria, progeria and other diseases. In the present investigation, we have developed two structure-based pharmacophore models from protein–ligand complex (3E33 and 3E37) obtained from the protein data bank. Molecular dynamics (MD) simulations were performed on the complexes, and different conformers of the same complex were generated. These conformers were undergone protein–ligand interaction fingerprint (PLIF) analysis, and the fingerprint bits have been used for structure-based pharmacophore model development. The PLIF results showed that Lys164, Tyr166, TrpB106 and TyrB361 are the major interacting residues in both the complexes. The RMSD and RMSF analyses on the MD-simulated systems showed that the absence of FPP in the complex 3E37 has significant effect in the conformational changes of the ligands. During this conformational change, some interactions between the protein and the ligands are lost, but regained after some simulations (after 2 ns). The structure-based pharmacophore models showed that the hydrophobic and acceptor contours are predominantly present in the models. The pharmacophore models were validated using reference compounds, which significantly identified as HITs with smaller RMSD values. The developed structure-based pharmacophore models are significant, and the methodology used in this study is novel from the existing methods (the original X-ray crystallographic coordination of the ligands is used for the model building). In our study, along with the original coordination of the ligand, different conformers of the same complex (protein–ligand) are used. It concluded that the developed methodology is significant for the virtual screening of novel molecules on different targets.  相似文献   
139.
140.
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