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   379723篇
  免费   24107篇
  国内免费   2809篇
耳鼻咽喉   5189篇
儿科学   8218篇
妇产科学   10085篇
基础医学   53175篇
口腔科学   11784篇
临床医学   30149篇
内科学   78501篇
皮肤病学   8553篇
神经病学   27253篇
特种医学   13972篇
外国民族医学   82篇
外科学   60621篇
综合类   9954篇
现状与发展   1篇
一般理论   64篇
预防医学   17441篇
眼科学   9447篇
药学   31005篇
  1篇
中国医学   2194篇
肿瘤学   28950篇
  2021年   2620篇
  2019年   2729篇
  2018年   4522篇
  2017年   3438篇
  2016年   3520篇
  2015年   4018篇
  2014年   5697篇
  2013年   7384篇
  2012年   10029篇
  2011年   10231篇
  2010年   6201篇
  2009年   5843篇
  2008年   9467篇
  2007年   10300篇
  2006年   10219篇
  2005年   9305篇
  2004年   8801篇
  2003年   8566篇
  2002年   8234篇
  2001年   28248篇
  2000年   28785篇
  1999年   23663篇
  1998年   5183篇
  1997年   4259篇
  1996年   3838篇
  1995年   3486篇
  1994年   3116篇
  1993年   2849篇
  1992年   16058篇
  1991年   14819篇
  1990年   14166篇
  1989年   13972篇
  1988年   12595篇
  1987年   12084篇
  1986年   11117篇
  1985年   10329篇
  1984年   6919篇
  1983年   5607篇
  1982年   2722篇
  1979年   5498篇
  1978年   3353篇
  1977年   2979篇
  1975年   2646篇
  1974年   3073篇
  1973年   2871篇
  1972年   2830篇
  1971年   2779篇
  1970年   2512篇
  1969年   2551篇
  1968年   2252篇
排序方式: 共有10000条查询结果,搜索用时 15 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