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   3545435篇
  免费   299459篇
  国内免费   14247篇
耳鼻咽喉   48170篇
儿科学   111311篇
妇产科学   89504篇
基础医学   561609篇
口腔科学   95216篇
临床医学   321877篇
内科学   631049篇
皮肤病学   91193篇
神经病学   306428篇
特种医学   141332篇
外国民族医学   305篇
外科学   547034篇
综合类   107219篇
现状与发展   25篇
一般理论   2376篇
预防医学   300733篇
眼科学   80816篇
药学   244580篇
  24篇
中国医学   9742篇
肿瘤学   168598篇
  2021年   56004篇
  2020年   35740篇
  2019年   58941篇
  2018年   72588篇
  2017年   55331篇
  2016年   61248篇
  2015年   75264篇
  2014年   109981篇
  2013年   175606篇
  2012年   99863篇
  2011年   100658篇
  2010年   119469篇
  2009年   123553篇
  2008年   87287篇
  2007年   91299篇
  2006年   101340篇
  2005年   96958篇
  2004年   98503篇
  2003年   89158篇
  2002年   77854篇
  2001年   111598篇
  2000年   105067篇
  1999年   102724篇
  1998年   66842篇
  1997年   64322篇
  1996年   62409篇
  1995年   58142篇
  1994年   52098篇
  1993年   48675篇
  1992年   73768篇
  1991年   70482篇
  1990年   66733篇
  1989年   65313篇
  1988年   60566篇
  1987年   59251篇
  1986年   56017篇
  1985年   56135篇
  1984年   50582篇
  1983年   45918篇
  1982年   42721篇
  1981年   40160篇
  1980年   37812篇
  1979年   41879篇
  1978年   36669篇
  1977年   33230篇
  1976年   30571篇
  1975年   29143篇
  1974年   30356篇
  1973年   29105篇
  1972年   27101篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
141.
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   
142.
143.
144.
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   
145.
146.
147.
148.
Abstract

Objective: To understand the origin of extremely high gonadotropin levels in a perimenopausal woman.

Methods: A 52-year-old woman with a 2?months of amenorrhea followed spontaneous menstrual cycles recovery was referred to our outpatient clinic with elevated follicle-stimulating hormone (FSH, 483 mUI/ml), luteinizing hormone (LH, 475 mUI/ml) and prolactin (PRL, 173?ng/ml). She was known to take levosulpiride. The gonadotropin levels did not fit with the clinical features.

Results: A gonadotroph tumor was ruled out. Further analysis confirmed constantly high FSH, LH and PRL levels. The measurements were repeated using different analytical platforms with different results. After serial dilutions, nonlinearity was present suggesting an immunoassay interference. After post-polyethylene glycol recovery, hormone levels appeared in the normal range. Anti-goat antibodies were recognized in the serum of the patient.

Conclusions: This case report shows a case of falsely abnormal high gonadotropin and PRL levels in a woman during menopause transition. In the clinical practice the evaluation of gonadotropin profile is not recommended at this age, but the abnormal levels stimulated further evaluation. An interference in the assay due to anti-goat antibodies resulted in abnormally high level of FSH and LH. A strict collaboration between clinicians and the laboratory is needed, when laboratory findings do not correspond to clinical findings.  相似文献   
149.
150.
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