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   1403582篇
  免费   90537篇
  国内免费   1840篇
耳鼻咽喉   18981篇
儿科学   39572篇
妇产科学   34668篇
基础医学   213403篇
口腔科学   39350篇
临床医学   123729篇
内科学   267819篇
皮肤病学   29995篇
神经病学   102507篇
特种医学   54711篇
外国民族医学   130篇
外科学   221944篇
综合类   24922篇
现状与发展   3篇
一般理论   334篇
预防医学   96738篇
眼科学   32198篇
药学   108883篇
  4篇
中国医学   3207篇
肿瘤学   82861篇
  2018年   14286篇
  2017年   10750篇
  2016年   12187篇
  2015年   13698篇
  2014年   18595篇
  2013年   27142篇
  2012年   38284篇
  2011年   40854篇
  2010年   23938篇
  2009年   22298篇
  2008年   38870篇
  2007年   41474篇
  2006年   41715篇
  2005年   39941篇
  2004年   38756篇
  2003年   37284篇
  2002年   36364篇
  2001年   73493篇
  2000年   75799篇
  1999年   62973篇
  1998年   15325篇
  1997年   13325篇
  1996年   13394篇
  1995年   12521篇
  1994年   11431篇
  1993年   10723篇
  1992年   47780篇
  1991年   47405篇
  1990年   46384篇
  1989年   45265篇
  1988年   41373篇
  1987年   40577篇
  1986年   37760篇
  1985年   36125篇
  1984年   26068篇
  1983年   22158篇
  1982年   11451篇
  1979年   23699篇
  1978年   16238篇
  1977年   13605篇
  1976年   12773篇
  1975年   14599篇
  1974年   17146篇
  1973年   16275篇
  1972年   15328篇
  1971年   14576篇
  1970年   13801篇
  1969年   12902篇
  1968年   11941篇
  1967年   10724篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Five years after treatment in a controlled trial, in which all had received self-exposure homework, a group of 40 agoraphobic outpatients retained marked improvement in agoraphobia, mood, and free-floating anxiety. Frequency of spontaneous panics decreased as much in those who had placebo and self-exposure as in those who received imipramine and self-exposure. Few patients, however, were completely well at 5 years and over half had received further treatment for agoraphobia during the follow-up. Patients who were still highly phobic at the end of the clinical trial were more often prescribed psychotropic medication during follow-up and remained phobic at 5 years. Phobic improvement had generalized more in those patients with very low than in those with moderate pretreatment Hamilton depression scores. Frequency of initial spontaneous panics did not predict outcome. Improvement in agoraphobia was associated with improved marital adjustment. Those who began with the best marital, work, and social adjustment were more improved in their phobias 5 years later.  相似文献   
992.
993.
994.
This article describes two studies that examine the nature of effective clinical performance among radiologic technology students. The first study includes the perspective of staff technologists on student performance, while the second study includes the perspective of clinical instructors, important dimensions of performance that are identified include organization, relationship with peers and staff, relationships with patients, flexibility, and initiative. These dimensions are linked to specific student behaviors in clinical practice.  相似文献   
995.
Psychiatric morbidity in Hobart's dependent aged   总被引:1,自引:0,他引:1  
Psychiatric morbidity in the dependent aged was studied in the elderly population of Hobart's nursing homes and long-stay hospitals. Only patients with home addresses in Hobart and who were admitted for the first time aged 70 years or over were included. Three hundred and twelve persons were interviewed with a standard interview, and an informant was interviewed when appropriate. The medical records were searched for diagnoses and drug treatments. Physical disability was rated on an ad hoc scale. Comparisons were made of the prevalence of dementia, depression and anxiety in different types of unit, and between these and two domiciliary samples, one of which received domiciliary nursing services (n = 100) and the other not (n = 100). The differential use of institutions by men and women, and a possible sex difference in the prevalence of dementia is discussed.  相似文献   
996.
Computer software developed in our laboratory (CMATRIX) was used to design a physiological pharmacokinetic model of nicotine absorption, distribution, metabolism and excretion in man. The model accommodates inhalation of nicotine from various environmental settings and physiological conditions in man. It was also used to predict pharmacokinetic behavior of cotinine arising from nicotine metabolism. Model-predicted variations in body-fluid nicotine levels confirm that nicotine is not an acceptable quantitative marker of environmental tobacco smoke (ETS) exposure. Though cotinine provides a more stable pattern, predicted interindividual variation suggests the need for specific strict sampling and monitoring guidelines for cotinine to be a reliable quantitative marker.  相似文献   
997.
Seven normal subjects received 0.25 mg/kg D-amphetamine orally, both after an overnight fast and again after a standard breakfast. Plasma levels, subjective and cardiovascular effects, and observer-rated activation were assessed hourly for 5 hr. Food did not affect amphetamine levels. Plasma levels peaked at 2-3 hr. Maximum cardiovascular effects generally occurred at 1 hr, whereas maximum behavioral and subjective effects occurred at 2 hr. Subjective and behavioral effects declined thereafter, in spite of substantial amphetamine levels. A separate group of 8 subjects received 0.5 mg/kg D-amphetamine orally. Plasma levels, subjective and cardiovascular effects, and activation ratings were assessed hourly for 4 hr. Maximum plasma levels were approximately twice those seen in the first group. In this case, plasma levels peaked at 3-4 hr; blood pressure and subjective and behavioral effects were all maximal at 2-3 hr and were declining by 4 hr, in spite of stable or rising plasma levels.  相似文献   
998.
999.
1000.
Individual crystallins, urea-soluble and urea-insoluble proteins were isolated from the nucleus and cortex of types I-IV cataractous lenses and normal lenses. The levels of protein sulphydryls (P-SH), disulphides (S-S), as well as surface (F-SH) and buried (S-SH) in these proteins were determined by reaction with 5, 5'-dithiotris- (2-nitrobenzoic acid) or performic acid oxidation followed by amino acid analysis. During nuclear colour development there is a progressive decrease in the sulphydryl content of the crystallins. In the nuclei of advanced cataractous lenses, the P-SH decreases to 10% of the levels found in the normal nucleus. Similar but smaller changes take place in the cortex. No specific changes were found between the crystallins, with the exception of beta S crystallin. The cysteine remains constant in all lens types suggesting no higher oxidation products are formed. There is a significant shift in the distribution of cysteine in the nucleus of type III and IV lenses. Urea-insoluble proteins are the predominant species, accounting for about 70% of the total cysteine pool. This is consistent with the accumulation of modified insoluble polypeptides during senile nuclear cataract formation.  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