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   499452篇
  免费   31932篇
  国内免费   3335篇
耳鼻咽喉   6470篇
儿科学   11753篇
妇产科学   12089篇
基础医学   69102篇
口腔科学   13958篇
临床医学   42018篇
内科学   103649篇
皮肤病学   9981篇
神经病学   38944篇
特种医学   17668篇
外国民族医学   83篇
外科学   77831篇
综合类   11585篇
现状与发展   2篇
一般理论   220篇
预防医学   27988篇
眼科学   12606篇
药学   39532篇
  2篇
中国医学   2445篇
肿瘤学   36793篇
  2021年   4895篇
  2020年   3006篇
  2019年   5047篇
  2018年   7236篇
  2017年   5424篇
  2016年   5836篇
  2015年   6683篇
  2014年   9531篇
  2013年   12801篇
  2012年   18263篇
  2011年   19060篇
  2010年   11011篇
  2009年   10338篇
  2008年   17245篇
  2007年   18592篇
  2006年   18104篇
  2005年   17200篇
  2004年   16268篇
  2003年   15449篇
  2002年   14870篇
  2001年   29387篇
  2000年   29628篇
  1999年   24837篇
  1998年   6585篇
  1997年   5452篇
  1996年   4772篇
  1995年   4411篇
  1994年   3892篇
  1993年   3622篇
  1992年   16697篇
  1991年   15408篇
  1990年   14681篇
  1989年   14450篇
  1988年   13069篇
  1987年   12526篇
  1986年   11511篇
  1985年   10798篇
  1984年   7466篇
  1983年   6109篇
  1982年   3405篇
  1981年   2829篇
  1979年   5843篇
  1978年   3689篇
  1977年   3310篇
  1975年   2910篇
  1974年   3338篇
  1973年   3119篇
  1972年   3029篇
  1971年   2929篇
  1969年   2680篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
In the 6th Basic Plan for Long-Term Electricity Supply and Demand (6th BPE) for Korea, for the first time, the environmental costs of air pollution caused by oxides of sulfur (SOx), oxides of nitrogen (NOx), and particulate matters (PM) from power plants were estimated and included. However, several deficiencies in evaluating the environmental costs were found. In this study, (1) the validity of the environmental costs used in the 6th BPE was assessed, (2) a systematic approach was suggested and used to improve the environmental costs estimation, and (3) the sensitivity of the cost of generating electricity to the environmental costs by fuel type with the proposed approach was discussed. We found that the applied environmental costs used in the 6th BPE did not fully include the demographic characteristics of Korea. By applying more realistic parameter values, it was found that the newly estimated environmental cost was about 23 times higher than the cost estimated in the original 6th BPE for coal-fired power plants and about 1.5 times higher for liquefied natural gas (LNG)-fired power plants, suggesting that LNG-fired power plants are more economical if using more realistic environmental costs. Thus, it is critical to check the validity of parameter values when calculating environmental costs.  相似文献   
7.
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   
8.
9.
10.
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