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   1706889篇
  免费   124405篇
  国内免费   3842篇
耳鼻咽喉   21836篇
儿科学   55992篇
妇产科学   46363篇
基础医学   242495篇
口腔科学   49231篇
临床医学   152331篇
内科学   336100篇
皮肤病学   38889篇
神经病学   131793篇
特种医学   64209篇
外国民族医学   246篇
外科学   259093篇
综合类   39372篇
现状与发展   4篇
一般理论   542篇
预防医学   125021篇
眼科学   40535篇
药学   124589篇
  7篇
中国医学   4559篇
肿瘤学   101929篇
  2021年   13511篇
  2019年   13982篇
  2018年   20568篇
  2017年   15542篇
  2016年   17000篇
  2015年   19307篇
  2014年   26736篇
  2013年   38581篇
  2012年   53655篇
  2011年   56305篇
  2010年   33228篇
  2009年   31106篇
  2008年   52133篇
  2007年   55403篇
  2006年   55833篇
  2005年   53033篇
  2004年   51236篇
  2003年   48550篇
  2002年   46762篇
  2001年   91866篇
  2000年   93685篇
  1999年   77033篇
  1998年   19794篇
  1997年   17318篇
  1996年   17441篇
  1995年   16794篇
  1994年   15323篇
  1993年   14092篇
  1992年   57420篇
  1991年   55311篇
  1990年   52998篇
  1989年   50799篇
  1988年   46152篇
  1987年   44963篇
  1986年   42265篇
  1985年   40010篇
  1984年   29370篇
  1983年   24932篇
  1982年   13912篇
  1979年   25542篇
  1978年   17581篇
  1977年   14909篇
  1976年   13882篇
  1975年   14571篇
  1974年   17636篇
  1973年   16951篇
  1972年   15678篇
  1971年   14457篇
  1970年   13436篇
  1969年   12519篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
Liposarcomas are extremely rare in the mediastinum. They may achieve considerable size before causing any symptoms. Mediastinal liposarcomas may invade surrounding structures like the pericardium or the superior vena cava. Complete surgical excision is the optimal treatment in resectable cases. Excision of adjacent structures like the pericardium may be needed if the tumor infiltrates them. We report on a case of a giant liposarcoma of the mediastinum involving both hemithoraces and extending into the neck, which was successfully managed by complete surgical excision.  相似文献   
82.
A series of 1-alkyl-3,4-dihydroisoquinolines and the related 4-alkyl-1,2-dihydro-benzo[f]isoquinolines was synthesized using reactions of dialkylbenzylcarbinols and their naphthyl analogs with alkylcyanides. Experiments showed that 1-alkyl-6,7-dimethoxy-3,4-dihydroisoquinolines typically produce a hypotensive action, while the benzo-annelated structures usually exhibit a hypertensive effects. The most active compound decreases the arterial pressure in cats by 52 Torr and the effect lasts for about 4 hours. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 40, No. 3, pp. 15–17, March, 2006.  相似文献   
83.
The authors discuss techniques for Monte Carlo (MC) cohort simulations that reduce the number of simulation replications required to achieve a given degree of precision for various output measures. Known as variance reduction techniques, they are often used in industrial engineering and operations research models, but they are seldom used in medical models. However, most MC cohort simulations are well suited to the implementation of these techniques. The authors discuss the cost of implementation versus the benefit of reduced replications.  相似文献   
84.
French asthma patients may be supervised by general practitioners (GPs) and/or specialists. Therefore, this study examined asthma management in patients exclusively supervised by specialists (SPE), GPs, (GP) and both (GP+SPE group), and compared the findings. Asthma patients were consecutively recruited in 348 pharmacies. Each patient completed a questionnaire providing data on personal characteristics, asthma management, perception of disease and asthma supervision. Asthma control was measured using the Asthma Control Test. Questionnaires were linked to computerised records of medications which had been dispensed before inclusion in the study. From the 1,256 patients (mean age = 36.1 yrs, 54.3% females), 11.4, 36.6, and 52.0% were placed in the SPE, GP, and GP+SPE groups, respectively. During the previous 4 weeks, most patients in the SPE group were properly controlled (52.2 versus 26.4 and 21.5% in GP and GP+SPE groups, respectively). The SPE group made more use of fixed combinations of long-acting beta agonist and inhaled corticosteroid, while receiving less short-acting beta agonists, antitussives and antibiotics. Striking differences in symptoms and asthma management were observed according to the type of asthma supervision. The current results strongly support the need to improve the management of asthma in primary care, and the coordination of care between general practitioners and specialists.  相似文献   
85.
86.
87.
88.
89.
90.
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