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   1125824篇
  免费   86611篇
  国内免费   2228篇
耳鼻咽喉   16609篇
儿科学   34062篇
妇产科学   34379篇
基础医学   164412篇
口腔科学   32371篇
临床医学   96985篇
内科学   214051篇
皮肤病学   22833篇
神经病学   88547篇
特种医学   45369篇
外国民族医学   213篇
外科学   177674篇
综合类   31241篇
现状与发展   3篇
一般理论   416篇
预防医学   84796篇
眼科学   26800篇
药学   83554篇
中国医学   2321篇
肿瘤学   58027篇
  2018年   10624篇
  2015年   10846篇
  2014年   15213篇
  2013年   23334篇
  2012年   30893篇
  2011年   32406篇
  2010年   19452篇
  2009年   18078篇
  2008年   30401篇
  2007年   33236篇
  2006年   32865篇
  2005年   32219篇
  2004年   31498篇
  2003年   30207篇
  2002年   28980篇
  2001年   47545篇
  2000年   48490篇
  1999年   41027篇
  1998年   11954篇
  1997年   11057篇
  1996年   10796篇
  1995年   10231篇
  1994年   9754篇
  1992年   33949篇
  1991年   33637篇
  1990年   32973篇
  1989年   31901篇
  1988年   29766篇
  1987年   29127篇
  1986年   27729篇
  1985年   26908篇
  1984年   20613篇
  1983年   17663篇
  1982年   11037篇
  1981年   10033篇
  1980年   9427篇
  1979年   20612篇
  1978年   14959篇
  1977年   12606篇
  1976年   11549篇
  1975年   12706篇
  1974年   15638篇
  1973年   15141篇
  1972年   14332篇
  1971年   13344篇
  1970年   12755篇
  1969年   12196篇
  1968年   11163篇
  1967年   10338篇
  1966年   9639篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Pharmaceutical Chemistry Journal - Three extracts were produced from the above-ground part of the meadowsweet Filipendula ulmaria (L.) Maxim. using water, 40% ethanol, and 70% ethanol. Comparative...  相似文献   
42.
43.
The catechol-O-methyltransferase (COMT) enzyme is a major determinant of prefrontal dopamine levels. The Val158Met polymorphism affects COMT enzymatic activity and has been associated with variation in executive function and affective processing. This study investigated the effect of COMT genotype on the flexible modulation of the balance between processing self-generated and processing stimulus-oriented information, in the presence or absence of affective distractors. Analyses included 124 healthy adult participants, who were also assessed on standard working memory (WM) tasks. Relative to Val carriers, Met homozygotes made fewer errors when selecting and manipulating self-generated thoughts. This effect was partly accounted for by an association between COMT genotype and visuospatial WM performance. We also observed a complex interaction between the influence of affective distractors, COMT genotype and sex on task accuracy: male, but not female, participants showed a sensitivity to the affective distractors that was dependent on COMT genotype. This was not accounted for by WM performance. This study provides novel evidence of the role of dopaminergic genetic variation on the ability to select and manipulate self-generated thoughts. The results also suggest sexually dimorphic effects of COMT genotype on the influence of affective distractors on executive function.  相似文献   
44.
45.
46.
47.
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   
48.
49.
50.
ABSTRACT

Purpose

To investigate the expression of IL-11 and its receptor IL-11Rα and to quantify density of CD163+ M2 macrophages in proliferative diabetic retinopathy (PDR).  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