首页 | 官方网站   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   74483篇
  免费   4581篇
  国内免费   3010篇
医药卫生   82074篇
  2024年   82篇
  2023年   554篇
  2022年   512篇
  2021年   719篇
  2020年   690篇
  2019年   361篇
  2018年   938篇
  2017年   878篇
  2016年   1015篇
  2015年   1019篇
  2014年   1170篇
  2013年   1549篇
  2012年   2137篇
  2011年   4778篇
  2010年   3090篇
  2009年   2268篇
  2008年   2651篇
  2007年   2450篇
  2006年   2429篇
  2005年   3479篇
  2004年   7966篇
  2003年   7339篇
  2002年   5705篇
  2001年   4683篇
  2000年   2674篇
  1999年   3285篇
  1998年   2404篇
  1997年   2078篇
  1996年   1322篇
  1995年   1116篇
  1994年   1168篇
  1993年   1779篇
  1992年   1504篇
  1991年   1289篇
  1990年   983篇
  1989年   833篇
  1988年   637篇
  1987年   520篇
  1986年   517篇
  1985年   251篇
  1984年   137篇
  1983年   92篇
  1982年   83篇
  1981年   70篇
  1980年   51篇
  1979年   73篇
  1978年   47篇
  1977年   63篇
  1975年   65篇
  1974年   55篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
6.
目的:探讨福赛类杆菌与人类唾液富脯蛋白相互作用的蛋白分子。方法:Western—blot方法。将人工合成唾液富脯蛋白用生物素标记,福赛类杆菌全菌蛋白凝胶电泳,半干转移至纤维膜上,观察二者的相互作用。结果:富脯蛋白能与分子量为85KD、65KD、60KD、以及49KD的福赛类杆菌蛋白发生结合。结论:福赛类杆菌存在与人类唾液富脯蛋白相互结合的粘附素。  相似文献   
7.
Objective Ligustrazine, also named as tetramethylpyrazine, is a compound purified from Ligusticum chuanxiong hort and has ever been testified to be a calcium antagonist. The present investigation was to determine the antinoci-ceptive effect of ligustrazine and, if any, the peripheral ionic mechanism involved. Methods Paw withdrawal Latency ( PWL) to noxious heating was measured in vivo and whole-cell patch recording was performed on small dorsal root ganglion (DRG) neurons. Results Intraplantar injection of ligustrazine (0.5 mg in 25μl) significantly prolonged the withdrawal latency of ipsilateral hindpaw to noxious heating in the rat. Ligustrazine not only reversibly inhibited high-voltage gated calcium current of dorsal root ganglion (DRG) neuron in dose-dependent manner with IC50 of 1.89 mmol/L, but also decreased tetrodotoxin (TTX) -resistant sodium current in relatively selective and dose-dependent manner with IC50 of 2.49 mmol/L. Conclusion The results suggested that ligustrazine could elevate the threshold of thermal nociception through inhibiting the high-voltage gated calcium current and TTX-resistant sodium current of DRG neuron in the rat.  相似文献   
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.
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-23

京公网安备 11010802026262号