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   380130篇
  免费   24175篇
  国内免费   2834篇
耳鼻咽喉   5201篇
儿科学   8242篇
妇产科学   10116篇
基础医学   53222篇
口腔科学   11805篇
临床医学   30212篇
内科学   78463篇
皮肤病学   8570篇
神经病学   27239篇
特种医学   13945篇
外国民族医学   82篇
外科学   60725篇
综合类   10030篇
现状与发展   1篇
一般理论   64篇
预防医学   17507篇
眼科学   9497篇
药学   31018篇
  2篇
中国医学   2207篇
肿瘤学   28991篇
  2021年   2650篇
  2019年   2771篇
  2018年   4560篇
  2017年   3479篇
  2016年   3559篇
  2015年   4060篇
  2014年   5752篇
  2013年   7428篇
  2012年   10088篇
  2011年   10262篇
  2010年   6233篇
  2009年   5882篇
  2008年   9499篇
  2007年   10341篇
  2006年   10275篇
  2005年   9327篇
  2004年   8833篇
  2003年   8553篇
  2002年   8226篇
  2001年   28253篇
  2000年   28793篇
  1999年   23660篇
  1998年   5166篇
  1997年   4256篇
  1996年   3828篇
  1995年   3479篇
  1994年   3105篇
  1993年   2846篇
  1992年   16054篇
  1991年   14818篇
  1990年   14157篇
  1989年   13962篇
  1988年   12580篇
  1987年   12065篇
  1986年   11106篇
  1985年   10322篇
  1984年   6915篇
  1983年   5600篇
  1982年   2719篇
  1979年   5479篇
  1978年   3350篇
  1977年   2974篇
  1975年   2641篇
  1974年   3066篇
  1973年   2865篇
  1972年   2830篇
  1971年   2777篇
  1970年   2513篇
  1969年   2546篇
  1968年   2251篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
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   
5.
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   
6.
7.
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