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   53514篇
  免费   3890篇
  国内免费   963篇
耳鼻咽喉   313篇
儿科学   2495篇
妇产科学   3285篇
基础医学   4450篇
口腔科学   627篇
临床医学   5485篇
内科学   13606篇
皮肤病学   850篇
神经病学   3597篇
特种医学   1241篇
外国民族医学   1篇
外科学   5816篇
综合类   3809篇
现状与发展   3篇
一般理论   13篇
预防医学   4626篇
眼科学   1719篇
药学   2472篇
  5篇
中国医学   577篇
肿瘤学   3377篇
  2024年   85篇
  2023年   618篇
  2022年   467篇
  2021年   788篇
  2020年   711篇
  2019年   372篇
  2018年   1128篇
  2017年   1082篇
  2016年   1250篇
  2015年   1203篇
  2014年   1173篇
  2013年   1615篇
  2012年   3215篇
  2011年   3895篇
  2010年   1801篇
  2009年   1639篇
  2008年   3472篇
  2007年   3397篇
  2006年   3038篇
  2005年   3298篇
  2004年   4105篇
  2003年   4024篇
  2002年   3106篇
  2001年   2413篇
  2000年   934篇
  1999年   953篇
  1998年   953篇
  1997年   799篇
  1996年   582篇
  1995年   416篇
  1994年   480篇
  1993年   478篇
  1992年   531篇
  1991年   477篇
  1990年   432篇
  1989年   394篇
  1988年   324篇
  1987年   307篇
  1986年   281篇
  1985年   200篇
  1984年   146篇
  1983年   140篇
  1982年   127篇
  1981年   127篇
  1980年   114篇
  1979年   99篇
  1978年   85篇
  1977年   84篇
  1975年   97篇
  1973年   91篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
5.
6.
7.
8.
Background: Large randomized trials show that in appropriately selected patients with left ventricular dysfunction, implantable cardioverter-defibrillators (ICDs) can improve overall survival at 2–5 years. Since direct implementation of the criteria used in the MADIT II and SCD-HeFT will lead to a marked rise in ICD implants, there is a growing fear that increased use of ICDs may cause a dramatic burden to health care systems. The ICD has traditionally been seen as an expensive form of treatment, which is difficult to accept at the first look. This is mainly due to the nonlinear character of the ICD investment, characterized by high initial expenditure, followed by a deferred pay-off in terms of clinical benefits. Cost-effectiveness analysis may help provide a different perspective on the problem of ICD cost, as may estimation of the daily cost of ICD treatment, assuming a time horizon of 5–7 years—a particularly interesting subject for further registry studies.
Methods and Results: Based on real expenditure data from 2002 to 2005, as recorded in the Search-MI Registry-Italian Sub-study of patients implanted on MADIT II indications, we estimated the daily costs associated with the device and leads. Over a 5–7 year time horizon, the average daily cost was estimated to be €4.60–€6.70. Translation of these figures into U.S. market conditions suggests a daily cost of around $7.90–$11.40.
Conclusions: These findings appear useful to help evaluate the affordability of ICD in comparison with other therapeutic options in a context of limited available economic resources.  相似文献   
9.
10.
We report a reliable method for determining DOPA levels in plasma and cerebrospinal fluid. The method is based on complete conversion of DOPA to dopamine and quantification by HPLC-ECD of the dopamine formed. Lower limit of detection was 0.5 nmol/l. No differences in plasma DOPA levels were found between normal children (0-15 yr, n = 60), normal adults (n = 39) and patients with essential hypertension (n = 40) or Parkinson's disease (no DOPA therapy, n = 30). In normal individuals and in patients with essential hypertension venous plasma levels were higher than arterial levels (10.2 vs 9.3 nmol/l, p less than 0.001, V/A ratio 1.11 (SD 0.08), n = 15). Sympathetic stimuli (standing, tilting, bicycle exercise, tyramine) did not influence DOPA levels. In untreated depressed patients (n = 10) and in non-parkinsonian neurological patients (n = 12) cerebrospinal fluid levels of DOPA were 4.5 (SD 2.4) and 5.2 (SD 1.3) nmol/l respectively. A direct method for the measurement of DOPA by HPLC-ECD after deproteinization of plasma is also described and compared with the conversion method. Good agreement was found when plasma DOPA levels exceeded 0.25 mumol/l (y(conversion method) = 0.943x (direct method) + 0.118; n = 60; r = 0.985). The direct method, because of greater simplicity and the possibility of simultaneous measurement of the DOPA metabolite 3-O-methyldopa, is the method of choice with plasma samples from DOPA-treated patients. In non-DOPA treated individuals the conversion method is superior and has proved to be an accurate and sensitive method for the determination of DOPA levels in plasma and cerebrospinal fluid.  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