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   379097篇
  免费   24915篇
  国内免费   2804篇
耳鼻咽喉   5186篇
儿科学   8209篇
妇产科学   10108篇
基础医学   53214篇
口腔科学   11800篇
临床医学   30168篇
内科学   78429篇
皮肤病学   8581篇
神经病学   27240篇
特种医学   13937篇
外国民族医学   82篇
外科学   60796篇
综合类   9958篇
现状与发展   1篇
一般理论   64篇
预防医学   17426篇
眼科学   9449篇
药学   31025篇
  1篇
中国医学   2194篇
肿瘤学   28948篇
  2021年   2620篇
  2019年   2737篇
  2018年   4538篇
  2017年   3450篇
  2016年   3529篇
  2015年   4038篇
  2014年   5717篇
  2013年   7414篇
  2012年   10061篇
  2011年   10246篇
  2010年   6212篇
  2009年   5859篇
  2008年   9479篇
  2007年   10313篇
  2006年   10247篇
  2005年   9320篇
  2004年   8827篇
  2003年   8558篇
  2002年   8238篇
  2001年   28307篇
  2000年   28810篇
  1999年   23689篇
  1998年   5174篇
  1997年   4254篇
  1996年   3836篇
  1995年   3480篇
  1994年   3114篇
  1993年   2846篇
  1992年   16065篇
  1991年   14836篇
  1990年   14163篇
  1989年   13969篇
  1988年   12591篇
  1987年   12082篇
  1986年   11120篇
  1985年   10331篇
  1984年   6930篇
  1983年   5606篇
  1982年   2722篇
  1979年   5488篇
  1978年   3354篇
  1977年   2976篇
  1975年   2644篇
  1974年   3067篇
  1973年   2871篇
  1972年   2830篇
  1971年   2775篇
  1970年   2512篇
  1969年   2544篇
  1968年   2253篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
Nevo  N.  Goldstein  A. L.  Staierman  M.  Eran  N.  Carmeli  I.  Rayman  S.  mnouskin  Y. 《Hernia》2022,26(6):1491-1499
Hernia - The minimally invasive surgical repair of combined inguinal and ventral hernias often requires shifting from one approach or plane to another. The traditional enhanced-view totally...  相似文献   
14.
15.
16.
17.
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   
18.
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   
19.
20.
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   
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