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   1279952篇
  免费   97877篇
  国内免费   1988篇
耳鼻咽喉   18431篇
儿科学   44373篇
妇产科学   35022篇
基础医学   182308篇
口腔科学   33601篇
临床医学   111381篇
内科学   258427篇
皮肤病学   28028篇
神经病学   100525篇
特种医学   51230篇
外国民族医学   660篇
外科学   196539篇
综合类   27057篇
现状与发展   1篇
一般理论   378篇
预防医学   95904篇
眼科学   27921篇
药学   94857篇
  2篇
中国医学   2442篇
肿瘤学   70730篇
  2018年   13153篇
  2017年   9977篇
  2016年   10914篇
  2015年   12388篇
  2014年   17190篇
  2013年   26269篇
  2012年   36085篇
  2011年   38109篇
  2010年   22840篇
  2009年   21844篇
  2008年   36696篇
  2007年   39305篇
  2006年   39566篇
  2005年   38498篇
  2004年   37641篇
  2003年   36493篇
  2002年   35832篇
  2001年   64023篇
  2000年   66544篇
  1999年   56438篇
  1998年   15138篇
  1997年   13763篇
  1996年   14207篇
  1995年   13461篇
  1994年   12772篇
  1993年   11801篇
  1992年   44586篇
  1991年   43487篇
  1990年   42236篇
  1989年   40149篇
  1988年   36911篇
  1987年   36263篇
  1986年   33643篇
  1985年   32296篇
  1984年   24156篇
  1983年   20280篇
  1982年   11733篇
  1981年   10702篇
  1980年   9521篇
  1979年   21353篇
  1978年   14830篇
  1977年   12540篇
  1976年   11702篇
  1975年   12629篇
  1974年   14673篇
  1973年   14125篇
  1972年   12949篇
  1971年   11732篇
  1970年   11055篇
  1969年   10028篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
Advancement in microelectromechanical system has facilitated the microfabrication of polymeric substrates and the development of the novel class of controlled drug delivery devices. These vehicles have specifically tailored three dimensional physical and chemical features which together, provide the capacity to target cell, stimulate unidirectional controlled release of therapeutics and augment permeation across the barriers. Apart from drug delivery devices microfabrication technology’s offer exciting prospects to generate biomimetic gastrointestinal tract models. BioMEMS are capable of analysing biochemical liquid sample like solution of metabolites, macromolecules, proteins, nucleic acid, cells and viruses. This review summarized multidisciplinary application of biomedical microelectromechanical systems in drug delivery and its potential in analytical procedures.  相似文献   
34.
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   
35.
36.
37.
38.
39.
This study used the National Survey of Ambulatory Surgery (NSAS) database to measure the incidence of and risk factors for symptoms in the ambulatory surgery center and problems within 24 h after isolated carpal tunnel release (CTR). The NSAS contained records on 400,000 adult patients with carpal tunnel syndrome who were treated with CTR in 2006, based on ICD-9 codes. The type of anesthesia used and factors associated with symptoms and problems were sought in bivariate and multivariable statistical analyses. The mean duration of the procedure was 16 ± 8.8 min. Only 5 % were performed under local anesthesia without sedation, 45 % with IV sedation, 28 % regional anesthesia, and 19 % general anesthesia. Symptoms in the ambulatory surgery center or a problem within 24 h after discharge were recorded in 10 % of patients, all of them minor and transient, including difficulties with pain and its treatment. The strongest risk factors were male sex, age of 45 years and older, and participation of an anesthesiologist. Local anesthesia and regional anesthesia were associated with more perioperative symptoms and postoperative problems. Most CTR are performed with some sedation in the United States. CTR is a safe procedure: one in 10 patients will experience a minor issue in the perioperative or immediate postoperative period.  相似文献   
40.
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