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   47646篇
  免费   3558篇
  国内免费   2000篇
耳鼻咽喉   168篇
儿科学   830篇
妇产科学   490篇
基础医学   6848篇
口腔科学   507篇
临床医学   3700篇
内科学   13421篇
皮肤病学   638篇
神经病学   3160篇
特种医学   910篇
外国民族医学   2篇
外科学   3704篇
综合类   5237篇
现状与发展   5篇
预防医学   2836篇
眼科学   877篇
药学   6205篇
  6篇
中国医学   1683篇
肿瘤学   1977篇
  2023年   472篇
  2022年   915篇
  2021年   1176篇
  2020年   1168篇
  2019年   1834篇
  2018年   1804篇
  2017年   1630篇
  2016年   1593篇
  2015年   1758篇
  2014年   2878篇
  2013年   3325篇
  2012年   2630篇
  2011年   2919篇
  2010年   2195篇
  2009年   2123篇
  2008年   2111篇
  2007年   2315篇
  2006年   2041篇
  2005年   1786篇
  2004年   1575篇
  2003年   1458篇
  2002年   1229篇
  2001年   1102篇
  2000年   936篇
  1999年   847篇
  1998年   722篇
  1997年   773篇
  1996年   577篇
  1995年   578篇
  1994年   504篇
  1993年   380篇
  1992年   335篇
  1991年   263篇
  1990年   201篇
  1989年   180篇
  1988年   151篇
  1987年   131篇
  1985年   467篇
  1984年   568篇
  1983年   454篇
  1982年   419篇
  1981年   406篇
  1980年   363篇
  1979年   324篇
  1978年   276篇
  1977年   208篇
  1976年   247篇
  1975年   250篇
  1974年   196篇
  1973年   174篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
The value of adding simeprevir (SMV) vs placebo (PBO) to peginterferon and ribavirin (PR) for treatment of chronic hepatitis C virus infection was examined using patient‐reported outcomes (PROs); further, concordance of PROs with virology endpoints and adverse events (AEs) was explored. Patients (= 768 SMV/PR,= 393 PBO/PR) rated fatigue (FSS), depressive symptoms (CES‐D) and functional impairment (WPAI: Hepatitis C Productivity, Daily Activity and Absenteeism) at baseline and throughout treatment in three randomised, double‐blind trials comparing the addition of SMV or PBO during initial 12 weeks of PR. PR was administered for 48 weeks (PBO group) and 24/48 weeks (SMV group) using a response‐guided therapy (RGT) approach. Mean PRO scores (except Absenteeism) worsened from baseline to Week 4 to the same extent in both groups but reverted after Week 24 for SMV/PR and only after Week 48 for PBO/PR. Accordingly, there was a significantly lower area under the curve (baseline–Week 60, AUC60) and fewer weeks with clinically important worsening of scores in the SMV/PR group at any time point. Incidences of patients with fatigue and anaemia AEs were similar in both groups, but FSS scores showed that clinically important increases in fatigue lasted a mean of 6.9 weeks longer with PBO/PR (P < 0.001). PRO score subgroup analysis indicated better outcomes for patients who met the criteria for RGT or achieved sustained virological response 12 weeks post‐treatment (SVR12); differences in mean PRO scores associated with fibrosis level were only observed with PBO/PR. Greater efficacy of SMV/PR enabled reduced treatment duration and reduced time with PR‐related AEs without adding to AE severity.  相似文献   
3.
4.
5.
目的:探讨老年人桡骨远端C型骨折的手术治疗与非手术治疗的疗效差异,评价两种方法的优缺点。方法回顾性分析2009-12—2011-12收治的老年桡骨远端C型骨折68例,按照治疗方法分为A组(手术组)及B组(非手术组),统计分析两组患者的临床资料。结果 A组33例, B组35例,平均随访21.5个月。两组患者的年龄、骨折类型均无差异(P>0.05);术后影像学指标A组优于B组,骨折愈合时间B组优于A组,治疗成本A组大于B组(P<0.05);Cooney评分早期A组优于B组,1年后两组无差异,两组的并发症无差异(P>0.05)。结论老年人桡骨远端C型骨折手术治疗较非手术治疗可获得更好的复位及早期功能,但远期功能恢复无差异。  相似文献   
6.
7.
8.
The hepatitis C virus (HCV) is a pandemic human pathogen posing a substantial health and economic burden in both developing and developed countries. Controlling the spread of HCV through behavioural prevention strategies has met with limited success and vaccine development remains slow. The development of antiviral therapeutic agents has also been challenging, primarily due to the lack of efficient cell culture and animal models for all HCV genotypes, as well as the large genetic diversity between HCV strains. On the other hand, the use of interferon-α-based treatments in combination with the guanosine analogue, ribavirin, achieved limited success, and widespread use of these therapies has been hampered by prevalent side effects. For more than a decade, the HCV RNA-dependent RNA polymerase (RdRp) has been targeted for antiviral development. Direct acting antivirals (DAA) have been identified which bind to one of at least six RdRp inhibitor-binding sites, and are now becoming a mainstay of highly effective and well tolerated antiviral treatment for HCV infection. Here we review the different classes of RdRp inhibitors and their mode of action against HCV. Furthermore, the mechanism of antiviral resistance to each class is described, including naturally occurring resistance-associated variants (RAVs) in different viral strains and genotypes. Finally, we review the impact of these RAVs on treatment outcomes with the newly developed regimens.  相似文献   
9.
10.
Condensation of thiourea 1 with diethyl malonate 2 in the presence of sodium methoxide furnished 4,6‐dihydroxy‐2‐mercaptopyrimidine 3 . Compound 3 on methylation with diazomethane followed by oxidation with H5IO6/CrO3 in ethyl acetate gave 4,6‐dimethoxy‐2‐methylsulphonylpyrimidine 5 . Compound 5 on condensation with 2‐mercapto‐6‐chlorobenzoic acid in the presence of a phase transfer catalyst, tetrabutylammonium bromide and sodium carbonate gave the title compound – pyrithiobac‐sodium 6 with an overall yield of > 35% starting from thiourea. Following the above standardized procedure, using [14C]‐thiourea in lieu of thiourea, 14C labelled product 6 , was synthesized with an overall radiochemical yield > 30% (with respect to [14C]‐thiourea) for further evaluations of environmental fate of 6 , in soils and plants. Copyright © 2006 John Wiley & Sons, Ltd.  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