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   2651923篇
  免费   191855篇
  国内免费   4985篇
耳鼻咽喉   34951篇
儿科学   87242篇
妇产科学   72883篇
基础医学   382296篇
口腔科学   76575篇
临床医学   242477篇
内科学   514355篇
皮肤病学   59328篇
神经病学   208398篇
特种医学   98789篇
外国民族医学   497篇
外科学   390215篇
综合类   59872篇
现状与发展   6篇
一般理论   1043篇
预防医学   208382篇
眼科学   62314篇
药学   194453篇
  12篇
中国医学   5871篇
肿瘤学   148804篇
  2019年   20913篇
  2018年   29573篇
  2017年   22420篇
  2016年   24670篇
  2015年   28241篇
  2014年   39249篇
  2013年   58489篇
  2012年   80601篇
  2011年   85305篇
  2010年   50137篇
  2009年   47326篇
  2008年   79812篇
  2007年   84954篇
  2006年   85238篇
  2005年   82070篇
  2004年   79181篇
  2003年   75533篇
  2002年   73086篇
  2001年   128331篇
  2000年   131263篇
  1999年   109510篇
  1998年   29815篇
  1997年   26420篇
  1996年   26709篇
  1995年   25444篇
  1994年   23504篇
  1993年   21850篇
  1992年   84333篇
  1991年   82089篇
  1990年   79189篇
  1989年   76555篇
  1988年   70186篇
  1987年   68716篇
  1986年   65072篇
  1985年   61529篇
  1984年   45989篇
  1983年   39613篇
  1982年   22843篇
  1979年   42084篇
  1978年   29838篇
  1977年   25248篇
  1976年   23527篇
  1975年   25017篇
  1974年   30435篇
  1973年   29679篇
  1972年   27702篇
  1971年   25777篇
  1970年   24187篇
  1969年   22732篇
  1968年   21184篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
41.
DNA methylation at CpG dinucleotides is an important epigenetic regulator common to virtually all mammalian cell types, but recent evidence indicates that during early postnatal development neuronal genomes also accumulate uniquely high levels of two alternative forms of methylation, non-CpG methylation and hydroxymethylation. Here we discuss the distinct landscape of DNA methylation in neurons, how it is established, and how it might affect the binding and function of protein readers of DNA methylation. We review studies of one critical reader of DNA methylation in the brain, the Rett syndrome protein methyl CpG-binding protein 2 (MeCP2), and discuss how differential binding affinity of MeCP2 for non-CpG and hydroxymethylation may affect the function of this methyl-binding protein in the nervous system.  相似文献   
42.
Objective: Report efficacy findings from three clinical trials (one phase 2 and two phase 3 [OPUS-1, OPUS-2]) of lifitegrast ophthalmic solution 5.0% for treatment of dry eye disease (DED).

Research design and methods: Three 84-day, randomized, double-masked, placebo-controlled trials. Adults (≥18 years) with DED were randomized (1:1) to lifitegrast 5.0% or matching placebo. Changes from baseline to day 84 in signs and symptoms of DED were analyzed.

Main outcome measures: Phase 2, pre-specified endpoint: inferior corneal staining score (ICSS; 0–4); OPUS-1, coprimary endpoints: ICSS and visual-related function subscale (0–4 scale); OPUS-2, coprimary endpoints: ICSS and eye dryness score (EDS, VAS; 0–100).

Results: Fifty-eight participants were randomized to lifitegrast 5.0% and 58 to placebo in the phase 2 trial; 293 to lifitegrast and 295 to placebo in OPUS-1; 358 to lifitegrast and 360 to placebo in OPUS-2. In participants with mild-to-moderate baseline DED symptomatology, lifitegrast improved ICSS versus placebo in the phase 2 study (treatment effect, 0.35; 95% CI, 0.05–0.65; p?=?0.0209) and OPUS-1 (effect, 0.24; 95% CI, 0.10–0.38; p?=?0.0007). Among more symptomatic participants (baseline EDS ≥40, recent artificial tear use), lifitegrast improved EDS versus placebo in a post hoc analysis of OPUS-1 (effect, 13.34; 95% CI, 2.35–24.33; nominal p?=?0.0178) and in OPUS-2 (effect, 12.61; 95% CI, 8.51–16.70; p?<?0.0001).

Limitations: Trials were conducted over 12 weeks; efficacy beyond this period was not assessed.

Conclusions: Across three trials, lifitegrast improved ICSS in participants with mild-to-moderate baseline symptomatology in two studies, and EDS in participants with moderate-to-severe baseline symptomatology in two studies. Based on the overall findings from these trials, lifitegrast shows promise as a new treatment option for signs and symptoms of DED.  相似文献   
43.
44.
45.
46.
In 1963, Goffman argued that forming a group based on shared stigma may provide benefits. However, there is no empirical research on whether perception that a separate, unique, coherent group exists (i.e., group entitativity) influences coping, such as educating others or secrecy, for the stigmatized individual or his or her spouse. Further, little is known about how spouses influence each other in terms of promoting the education of others about a stigmatizing condition, especially when it comes to the role of believing that stigma-based groups, to which they may both belong, exist. This study provides a step toward bridging this gap in the research by applying the label management model in efforts to understand coping for couples in which one spouse is diagnosed with genetic mutations leading to alpha-1 antitrypsin deficiency (AATD). This study included 50 married couples in which one spouse is diagnosed with genetic mutations leading to alpha-1 antitrypsin deficiency (AATD). We found that group entitativity related to those with AATD counterbalanced the influence of genetic stigma on spouses’ intentions to keep the diagnosis secret or to educate others about it. Intrapersonal and interpersonal influences appeared among spouses. Attention is needed on the power of creating groups for stigmatized persons and their relatives. Indeed, people live within a dynamic world of group entities, and multiple social identities including spousal and familial. While attention has been paid to the diffusion of stigmas to loved ones, less has been paid to the uplift of group entities for them.  相似文献   
47.
48.
49.
50.
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