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   1715499篇
  免费   128071篇
  国内免费   3832篇
耳鼻咽喉   22123篇
儿科学   56613篇
妇产科学   46947篇
基础医学   244348篇
口腔科学   49354篇
临床医学   153356篇
内科学   338535篇
皮肤病学   39199篇
神经病学   133501篇
特种医学   64580篇
外国民族医学   244篇
外科学   260007篇
综合类   39354篇
现状与发展   4篇
一般理论   571篇
预防医学   126023篇
眼科学   40639篇
药学   124882篇
  7篇
中国医学   4481篇
肿瘤学   102634篇
  2021年   13111篇
  2019年   13883篇
  2018年   20336篇
  2017年   15502篇
  2016年   16930篇
  2015年   19297篇
  2014年   26687篇
  2013年   38707篇
  2012年   53707篇
  2011年   56463篇
  2010年   33397篇
  2009年   31236篇
  2008年   52489篇
  2007年   55820篇
  2006年   56258篇
  2005年   53486篇
  2004年   51694篇
  2003年   49029篇
  2002年   47328篇
  2001年   92446篇
  2000年   94313篇
  1999年   77585篇
  1998年   19987篇
  1997年   17492篇
  1996年   17631篇
  1995年   16947篇
  1994年   15490篇
  1993年   14317篇
  1992年   57944篇
  1991年   55786篇
  1990年   53426篇
  1989年   51228篇
  1988年   46581篇
  1987年   45369篇
  1986年   42648篇
  1985年   40416篇
  1984年   29710篇
  1983年   25224篇
  1982年   14114篇
  1979年   25827篇
  1978年   17778篇
  1977年   15084篇
  1976年   14072篇
  1975年   14733篇
  1974年   17822篇
  1973年   17140篇
  1972年   15854篇
  1971年   14636篇
  1970年   13584篇
  1969年   12654篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
European Journal of Orthopaedic Surgery & Traumatology - The goals of this study were to compare patient satisfaction and wound-related complications in patients receiving 2-octyl cyanoacrylate...  相似文献   
64.
65.
66.
67.
Individuals with sudden unilateral deafness offer a unique opportunity to study plasticity of the binaural auditory system in adult humans. Stimulation of the intact ear results in increased activity in the auditory cortex. However, there are no reports of changes at sub-cortical levels in humans. Therefore, the aim of the present study was to investigate changes in sub-cortical activity immediately before and after the onset of surgically induced unilateral deafness in adult humans. Click-evoked auditory brainstem responses (ABRs) to stimulation of the healthy ear were recorded from ten adults during the course of translabyrinthine surgery for the removal of a unilateral acoustic neuroma. This surgical technique always results in abrupt deafferentation of the affected ear. The results revealed a rapid (within minutes) reduction in latency of wave V (mean pre = 6.55 ms; mean post = 6.15 ms; p < 0.001). A latency reduction was also observed for wave III (mean pre = 4.40 ms; mean post = 4.13 ms; p < 0.001). These reductions in response latency are consistent with functional changes including disinhibition or/and more rapid intra-cellular signalling affecting binaurally sensitive neurons in the central auditory system. The results are highly relevant for improved understanding of putative physiological mechanisms underlying perceptual disorders such as tinnitus and hyperacusis.  相似文献   
68.
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   
69.
70.
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   
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