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   1413470篇
  免费   104256篇
  国内免费   2202篇
耳鼻咽喉   18497篇
儿科学   45130篇
妇产科学   37806篇
基础医学   208669篇
口腔科学   37731篇
临床医学   132581篇
内科学   279413篇
皮肤病学   29773篇
神经病学   116748篇
特种医学   52016篇
外国民族医学   278篇
外科学   200824篇
综合类   27723篇
现状与发展   6篇
一般理论   760篇
预防医学   115797篇
眼科学   32239篇
药学   102241篇
  7篇
中国医学   2203篇
肿瘤学   79486篇
  2021年   11818篇
  2019年   12413篇
  2018年   16328篇
  2017年   12458篇
  2016年   13747篇
  2015年   15961篇
  2014年   22204篇
  2013年   34048篇
  2012年   46995篇
  2011年   50021篇
  2010年   28805篇
  2009年   27572篇
  2008年   47422篇
  2007年   50587篇
  2006年   49774篇
  2005年   49199篇
  2004年   47257篇
  2003年   45185篇
  2002年   43747篇
  2001年   57276篇
  2000年   58003篇
  1999年   49442篇
  1998年   15349篇
  1997年   13925篇
  1996年   14089篇
  1995年   13247篇
  1994年   12324篇
  1992年   39075篇
  1991年   38492篇
  1990年   37178篇
  1989年   35937篇
  1988年   33377篇
  1987年   32628篇
  1986年   31233篇
  1985年   29565篇
  1984年   22972篇
  1983年   20172篇
  1982年   12740篇
  1981年   11574篇
  1979年   21604篇
  1978年   16174篇
  1977年   13452篇
  1976年   12434篇
  1975年   13303篇
  1974年   16095篇
  1973年   15782篇
  1972年   14841篇
  1971年   13782篇
  1970年   12970篇
  1969年   12252篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
The present study demonstrates that alcohol-induced memory impairment can be attenuated by pretreatment with an oral tryptophan supplementation. These results provide support for the role of a brain serotonin deficit in this impairment and highlight the impact a dietary manipulation can have on a complex behavioral process.  相似文献   
74.
75.
The Dundee Memory Clinic was established in 1991. This paper reviews the diagnosis of the first 150 attenders and compares the findings with those of other memory clinics.  相似文献   
76.
This study examines the relationships between patient characteristics and surrogate decision maker characteristics on surrogates' preferences for life-sustaining treatments. Caucasian and African-American caregivers and noncaregivers (n=110) responded to a vignette involving a medical crisis in a hospitalized older man who suffered cardiac arrest, one of the most common causes of death among older Americans. This man was described as either a cognitively intact or moderately demented family member. Participants made decisions regarding cardiopulmonary resuscitation (CPR), CPR and ventilation, and CPR and tube feeding. Analyses followed a 2 (cognitive status) 2 (caregiving status) 2 (racial background) analysis of covariance design, with education and income used as covariates. In general, participants were less likely to initiate life-sustaining treatments in demented patients. Caucasian caregivers were less likely to initiate CPR and ventilation and CPR and tube feeding. Results indicate that characteristics of the patient and the interplay between cultural issues and experience with caregiving affect surrogate judgements regarding life-sustaining treatments.  相似文献   
77.
Choristomas, masses of normal tissues in aberrant locations, contain smooth muscle fibers and fibrous tissues. We describe the MR imaging features of two choristomas located in the internal auditory canals and arising from the facial and vestibulocochlear nerves. Both lesions enhanced with contrast material. In one case, enhancement was seen in the geniculate ganglion and greater superficial petrosal nerve. In the other, a medial component enhanced less than the lateral component did.  相似文献   
78.
summary The aetiology of denture stomatitis is not clear from the literature. Some studies show its aetiology as Candida albicans, while other reports point out the significance of microorganisms. In this study the existence of C. albicans and microorganisms was investigated in subjects with and without denture stomatitis. The results showed that a combination of C. albicans and microorganisms is more likely to be responsible for denture stomatitis.  相似文献   
79.
Piecewise constant incidence models were developed to estimate the force of infection in women from age-and time-specific antenatal or neonatal seroprevalence data. Differential inclusion of infected women in sero-surveys compared to uninfected women was taken into account, with respect to both changes in inclusion rate following infection, and changes in relative inclusion rate over calendar time. These models were applied to anonymous HIV seroprevalence data collected from neonates born to black and Hispanic women in New York City 1988-1992, with incidence and fertility parameters estimated by maximum likelihood. Estimates of inclusion rate parameters accorded well with what is known about the natural history of HIV. The data could not distinguish between additive and multiplicative combination of the effects of age and time on incidence. Incidence was strongly dependent on age with the highest incidence in women aged 20-34 years. There was strong evidence that incidence had been falling in Hispanic women since 1982-1984. The results illustrate the extent to which trends in incidence over time may be confounded by changes in the relative inclusion rate of infected and uninfected women.  相似文献   
80.
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