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   932045篇
  免费   66353篇
  国内免费   1342篇
耳鼻咽喉   12959篇
儿科学   24378篇
妇产科学   23236篇
基础医学   132945篇
口腔科学   28261篇
临床医学   80554篇
内科学   183274篇
皮肤病学   19228篇
神经病学   72255篇
特种医学   36799篇
外国民族医学   79篇
外科学   152085篇
综合类   18043篇
现状与发展   1篇
一般理论   234篇
预防医学   61738篇
眼科学   21309篇
药学   72557篇
  3篇
中国医学   2162篇
肿瘤学   57640篇
  2018年   8962篇
  2017年   7027篇
  2016年   7768篇
  2015年   8859篇
  2014年   11990篇
  2013年   17502篇
  2012年   24090篇
  2011年   25055篇
  2010年   14808篇
  2009年   14272篇
  2008年   24625篇
  2007年   25699篇
  2006年   26496篇
  2005年   25434篇
  2004年   24572篇
  2003年   23615篇
  2002年   23157篇
  2001年   54729篇
  2000年   56544篇
  1999年   46952篇
  1998年   10735篇
  1997年   9471篇
  1996年   9594篇
  1995年   8927篇
  1994年   8279篇
  1993年   7597篇
  1992年   35491篇
  1991年   33915篇
  1990年   32737篇
  1989年   31873篇
  1988年   28998篇
  1987年   28253篇
  1986年   26290篇
  1985年   25147篇
  1984年   17834篇
  1983年   15146篇
  1982年   7796篇
  1981年   6772篇
  1979年   15783篇
  1978年   10600篇
  1977年   9052篇
  1976年   7873篇
  1975年   8628篇
  1974年   10467篇
  1973年   9859篇
  1972年   9358篇
  1971年   8852篇
  1970年   8428篇
  1969年   7924篇
  1968年   7201篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Facial reanimation after acoustic neuroma excision is currently accomplished using a variety of surgical techniques. A multi-institutional survey of patient perceptions of facial reanimation success was accomplished by mailing a questionnaire to 809 randomly selected members of the Acoustic Neuroma Association. Four hundred sixty patients who underwent 296 reanimation procedures responded. Facial to hypoglossal nerve anastomosis, tarsorrhaphy, and upper eyelid implants were most frequently performed. The patient's estimations of initial deficit, spontaneous recovery, and overall satisfaction with the reanimation procedures are discussed.  相似文献   
102.
103.
104.
Abstract: The dependence of transient pressure characteristics of a ventricular assist device (VAD) on the compliance of its housing and cannulas was investigated in a mock circulation. The peak rate of change of pressure ( dP/dt max) values was greater in the cannulas than other compartments and was associated with valve closure-induced pressure oscillations. When cannula compliance was increased from 0.0057 to 0.0129 cm3/mm Hg, these values decreased by ˜20%, and outflow cannula pressure oscillation frequency decreased from 17.5 Hz by 35%. This trend was also apparent in the inflow. A VAD housing compliance increase from 0.0162 to 0.0483 cm3/mm Hg caused a dP/dt max decrease of 30% in both the blood chamber and the outflow cannula. The effect of this change on the inflow was weaker implying that housing absorbs the energy associated with outflow deceleration more effectively than the inflow. These findings suggest that increasing VAD housing and cannulas compliance can improve hydrodynamic performance.  相似文献   
105.
106.
107.
An analysis of mortality data for the years 1982-5 was carried out for the Micronesian population (aged 15 years and over) of the central Pacific Island, Nauru. Among males, the most common causes of death were circulatory system disorders (33.3%), accidents (25.2%), and diabetes mellitus (12.1%). The majority of accidents occurred in the 15-34 year age group and involved motor vehicles. Among females, neoplasms (almost all lung and cervix) (22.4%), circulatory system disorders (20.7%), and diabetes mellitus (17.2%) were the most common causes of death. When accidents are excluded, 59.4% of deaths were in persons with diabetes. Compared with Australia, mortality rates in almost all age groups were at least five times higher for males and females for a comparable period. Nauruan life expectancy (39.5 years for men and 48.5 years for women) is one of the lowest in the world. These data confirm the high mortality associated with diabetes mellitus in Nauruans as evidenced in earlier studies. Modernization of this society through the affluence acquired by the mining of phosphate has led to serious public health problems relating to non-communicable diseases so that the mortality trends now mirror those of developed societies.  相似文献   
108.
109.
110.
In the doubly-labelled water (2H2(18)O) method for the measurement of carbon dioxide production rate in man, single exponential disappearance curves for 2H2O and H2(18)O in body water are used; the precision with which the slopes and intercepts of the curves are estimated determines the precision of the estimate of carbon dioxide production rate. In studies with infants, and in computer simulations, the effect of different experimental regimes on the overall precision of the carbon dioxide production estimate was investigated. When the number of data points used was progressively reduced by shortening the total observation period from 7 d (about 3 biological half-lives for the isotopes) to 1 d there was a deleterious effect on precision and in the infants there was an upward bias in the values for carbon dioxide production. When the number of data points was reduced by removing points from the middle of the exponential curves with the maintenance of the 7-d experimental period, precision was also reduced but by less than in the former procedure and there were no consistent trends in the average values for carbon dioxide production.  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