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   1271130篇
  免费   95346篇
  国内免费   1593篇
耳鼻咽喉   16419篇
儿科学   41222篇
妇产科学   35103篇
基础医学   190292篇
口腔科学   34912篇
临床医学   118650篇
内科学   249297篇
皮肤病学   27387篇
神经病学   102565篇
特种医学   47100篇
外国民族医学   265篇
外科学   179702篇
综合类   25808篇
现状与发展   3篇
一般理论   570篇
预防医学   105132篇
眼科学   28146篇
药学   92967篇
  7篇
中国医学   2053篇
肿瘤学   70469篇
  2018年   13731篇
  2017年   10539篇
  2016年   11475篇
  2015年   13273篇
  2014年   18264篇
  2013年   27795篇
  2012年   38062篇
  2011年   40475篇
  2010年   23350篇
  2009年   22511篇
  2008年   38213篇
  2007年   40851篇
  2006年   40419篇
  2005年   39559篇
  2004年   38062篇
  2003年   36398篇
  2002年   35255篇
  2001年   56074篇
  2000年   57108篇
  1999年   48160篇
  1998年   13489篇
  1997年   12306篇
  1996年   12710篇
  1995年   11986篇
  1994年   11164篇
  1993年   10452篇
  1992年   38244篇
  1991年   37702篇
  1990年   36469篇
  1989年   35295篇
  1988年   32713篇
  1987年   32055篇
  1986年   30550篇
  1985年   28823篇
  1984年   21985篇
  1983年   19228篇
  1982年   11410篇
  1981年   10366篇
  1979年   20967篇
  1978年   15419篇
  1977年   12824篇
  1976年   11865篇
  1975年   12828篇
  1974年   15607篇
  1973年   15392篇
  1972年   14528篇
  1971年   13559篇
  1970年   12797篇
  1969年   12071篇
  1968年   11235篇
排序方式: 共有10000条查询结果,搜索用时 13 毫秒
61.
62.
The prevalence of heavy alcohol consumption is a major problem of increasing proportions throughout the world. Although alcohol sensitizing drugs and more recently serotonin uptake inhibitors are drug interventions with some following, their long term beneficial consequences have yet to be demonstrated. In recent years, we have demonstrated that manipulating activity in the renin-angiotensin system will dramatically alter voluntary alcohol consumption in rats. Based on these findings, the present study evaluated the ability of a class of drugs known as the angiotensin converting enzyme inhibitors to reduce voluntary alcohol drinking in laboratory animals. These drugs prevent the conversion of angiotensin I to angiotensin II. They have been licensed for use in Europe and North America and are indicated in the treatment of hypertension. Our experiments showed that both captopril (Capoten, Squibb) and enalapril (Vasotec, Merck Sharpe & Dohme) can reduce alcohol drinking in both normotensive and hypertensive animals regardless of whether the pattern of intake is in a bout or of a less exaggerated nature. Furthermore, this change in alcohol intake can occur without concomitant changes in blood pressure, plasma renin activity, overall fluid balance, or the distribution and metabolism of alcohol. Taken together these findings suggest that the angiotensin converting enzyme inhibitors should be evaluated in a clinical setting for they may prove to be a useful new treatment or treatment adjunct for alcohol abuse in humans.  相似文献   
63.
64.
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   
65.
66.
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   
67.
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   
68.
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   
69.
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   
70.
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   
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