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   379760篇
  免费   24917篇
  国内免费   2811篇
耳鼻咽喉   5231篇
儿科学   8229篇
妇产科学   10091篇
基础医学   53221篇
口腔科学   11802篇
临床医学   30190篇
内科学   78639篇
皮肤病学   8578篇
神经病学   27243篇
特种医学   13951篇
外国民族医学   82篇
外科学   60957篇
综合类   9959篇
现状与发展   1篇
一般理论   64篇
预防医学   17457篇
眼科学   9490篇
药学   31037篇
  1篇
中国医学   2194篇
肿瘤学   29071篇
  2021年   2638篇
  2019年   2754篇
  2018年   4556篇
  2017年   3461篇
  2016年   3547篇
  2015年   4046篇
  2014年   5715篇
  2013年   7406篇
  2012年   10059篇
  2011年   10248篇
  2010年   6228篇
  2009年   5876篇
  2008年   9510篇
  2007年   10337篇
  2006年   10252篇
  2005年   9346篇
  2004年   8851篇
  2003年   8574篇
  2002年   8262篇
  2001年   28317篇
  2000年   28829篇
  1999年   23713篇
  1998年   5181篇
  1997年   4263篇
  1996年   3849篇
  1995年   3497篇
  1994年   3117篇
  1993年   2857篇
  1992年   16076篇
  1991年   14833篇
  1990年   14187篇
  1989年   13985篇
  1988年   12617篇
  1987年   12080篇
  1986年   11122篇
  1985年   10330篇
  1984年   6922篇
  1983年   5605篇
  1982年   2724篇
  1979年   5486篇
  1978年   3356篇
  1977年   2983篇
  1975年   2643篇
  1974年   3068篇
  1973年   2872篇
  1972年   2836篇
  1971年   2775篇
  1970年   2510篇
  1969年   2545篇
  1968年   2252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.
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   
20.
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