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   3236220篇
  免费   257139篇
  国内免费   6669篇
耳鼻咽喉   46003篇
儿科学   102331篇
妇产科学   89249篇
基础医学   453365篇
口腔科学   92566篇
临床医学   295853篇
内科学   632373篇
皮肤病学   69072篇
神经病学   272252篇
特种医学   127120篇
外国民族医学   1186篇
外科学   485308篇
综合类   78381篇
现状与发展   4篇
一般理论   1332篇
预防医学   262734篇
眼科学   76535篇
药学   236681篇
  5篇
中国医学   6559篇
肿瘤学   171119篇
  2018年   34634篇
  2017年   26584篇
  2016年   29529篇
  2015年   33367篇
  2014年   48033篇
  2013年   72750篇
  2012年   98130篇
  2011年   103752篇
  2010年   61190篇
  2009年   58557篇
  2008年   97461篇
  2007年   103455篇
  2006年   104497篇
  2005年   101672篇
  2004年   97557篇
  2003年   93849篇
  2002年   91813篇
  2001年   150916篇
  2000年   155651篇
  1999年   131081篇
  1998年   38441篇
  1997年   34827篇
  1996年   34490篇
  1995年   33052篇
  1994年   30759篇
  1993年   28831篇
  1992年   103606篇
  1991年   99603篇
  1990年   95948篇
  1989年   92225篇
  1988年   85535篇
  1987年   84142篇
  1986年   79301篇
  1985年   75784篇
  1984年   57851篇
  1983年   49282篇
  1982年   30199篇
  1981年   26865篇
  1979年   53517篇
  1978年   37806篇
  1977年   31679篇
  1976年   29789篇
  1975年   31038篇
  1974年   38164篇
  1973年   36474篇
  1972年   34221篇
  1971年   31476篇
  1970年   29767篇
  1969年   27683篇
  1968年   25629篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
We present a patient with both dynamic left ventricular outflow tract obstruction and valvular aortic stenosis. The aortic valve was calcified, and velocities and gradients measured by continuous‐wave Doppler met standard criteria for severe aortic stenosis. The increased subvalvular velocities invalidated assumptions of the simplified Bernoulli equation; correction using the longer form of the Bernoulli equation suggested a lower but still significant gradient. The complex shape of the subvalvular spectral Doppler envelope indicated supranormal systolic function and dynamic left ventricular outflow obstruction. Left heart catheterization with an end‐hole catheter was required to determine the subvalvular and valvular components of the obstruction.  相似文献   
102.
103.
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   
104.
105.
106.
107.
Guidelines and consensus on the management of patients with acne aim to give evidence-based, expert-group recommendations. This review compares current guidelines and consensus articles to provide a compilation of recommendations on the treatment of acne with oral isotretinoin. Ten common, relevant, clinical questions are addressed, based on published recommendations, including the indications of isotretinoin, the proposed daily dose, the cumulative isotretinoin dose and the laboratory monitoring needed. Recommendations on special considerations are also addressed, including the timing of procedures and the question of an association of depression or inflammatory bowel disease with isotretinoin. A major limitation is the use of different classification systems for acne across guidelines. The recommended daily dose ranges from 0.3 to 0.5 mg/kg in the European guidelines to up to 1 mg/kg in the US guidelines. A specific duration of treatment of at least 6 months is only recommended in the European guidelines. All guidelines report the need of strict pregnancy prevention measures. The European, French and US guidelines recommend to monitor for symptoms of depression. Important clinical questions that are inconsistently addressed in guidelines include the age indication, the recommendation for a cumulative dose, the timing of procedures, the association of isotretinoin with IBD, the recommendation for preventing acne flares and for appropriate laboratory monitoring. These topics should be clearly included in the recommendations of guidelines as they are often raised in everyday clinical practice.  相似文献   
108.
109.
110.
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