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   1572466篇
  免费   109504篇
  国内免费   3277篇
耳鼻咽喉   23163篇
儿科学   48798篇
妇产科学   47131篇
基础医学   223958篇
口腔科学   46173篇
临床医学   132444篇
内科学   305737篇
皮肤病学   35377篇
神经病学   123007篇
特种医学   62726篇
外国民族医学   476篇
外科学   244916篇
综合类   37465篇
现状与发展   6篇
一般理论   580篇
预防医学   108903篇
眼科学   37097篇
药学   117131篇
  3篇
中国医学   3628篇
肿瘤学   86528篇
  2018年   14781篇
  2016年   13160篇
  2015年   14760篇
  2014年   20498篇
  2013年   31332篇
  2012年   40497篇
  2011年   42761篇
  2010年   25957篇
  2009年   24879篇
  2008年   40814篇
  2007年   44591篇
  2006年   45015篇
  2005年   43440篇
  2004年   42179篇
  2003年   40762篇
  2002年   39983篇
  2001年   73562篇
  2000年   75458篇
  1999年   63914篇
  1998年   17066篇
  1997年   15664篇
  1996年   15022篇
  1995年   14197篇
  1994年   13292篇
  1992年   49158篇
  1991年   47886篇
  1990年   47053篇
  1989年   45851篇
  1988年   42657篇
  1987年   41984篇
  1986年   40202篇
  1985年   38229篇
  1984年   28596篇
  1983年   24312篇
  1982年   14614篇
  1981年   13222篇
  1979年   27479篇
  1978年   19615篇
  1977年   17023篇
  1976年   15396篇
  1975年   17557篇
  1974年   20790篇
  1973年   20344篇
  1972年   19364篇
  1971年   18144篇
  1970年   17283篇
  1969年   16491篇
  1968年   15568篇
  1967年   14012篇
  1966年   13139篇
排序方式: 共有10000条查询结果,搜索用时 640 毫秒
61.
62.
63.
Porocarcinoma is an unusual, locally aggressive and potentially fatal neoplasm. Several cutaneous malignancies have been described in association with porocarcinoma, including squamous cell carcinoma, basal cell carcinoma and tricholemmal carcinoma. Previous reports have indicated that the occurrence of malignant tumours in combination with porocarcinoma is extremely rare, in particular with regard to Bowen disease (BD). We report an uncommon case of porocarcinoma occurring synchronously in a single BD lesion in a 63‐year‐old woman with multiple BD lesions. The clinical and histological findings confirmed this diagnosis.  相似文献   
64.
Children who expect they can bring about good outcomes and avoid bad outcomes tend to experience more personal successes. Little is known about factors that contribute to these ‘control expectancies’. The purpose of the present study was to determine whether children's internal control expectancies occur in the context of parents’ internal control expectancies, low family strain, and high family cohesiveness and whether these factors are more strongly related to daughters’ than sons’ control expectancies. A community sample of 85 children aged 9–11 years and their parents (85 mothers; 63 fathers) completed rating scales. Fathers’ more internal control expectancies and mothers’ reports of fewer family strains were associated with daughters’ but not sons’ greater internal control expectancies, and greater family cohesiveness was related to both daughters’ and sons’ internal control orientations. These findings suggest that family factors may contribute to children's, particularly daughters’, development of internal control expectancies.  相似文献   
65.
66.
67.
68.
69.
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   
70.
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