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   2536999篇
  免费   214418篇
  国内免费   15493篇
耳鼻咽喉   35796篇
儿科学   74506篇
妇产科学   65139篇
基础医学   354226篇
口腔科学   70545篇
临床医学   237792篇
内科学   491224篇
皮肤病学   49883篇
神经病学   209292篇
特种医学   101900篇
外国民族医学   983篇
外科学   377032篇
综合类   85097篇
现状与发展   40篇
一般理论   995篇
预防医学   201541篇
眼科学   59920篇
药学   195858篇
  190篇
中国医学   15133篇
肿瘤学   139818篇
  2021年   25544篇
  2019年   23237篇
  2018年   30493篇
  2017年   24587篇
  2016年   25940篇
  2015年   31599篇
  2014年   43615篇
  2013年   60107篇
  2012年   82209篇
  2011年   86907篇
  2010年   51897篇
  2009年   48079篇
  2008年   78219篇
  2007年   81987篇
  2006年   82551篇
  2005年   80416篇
  2004年   74592篇
  2003年   71776篇
  2002年   70172篇
  2001年   115163篇
  2000年   119473篇
  1999年   101507篇
  1998年   29933篇
  1997年   27702篇
  1996年   27104篇
  1995年   26247篇
  1994年   24579篇
  1993年   22389篇
  1992年   80360篇
  1991年   77270篇
  1990年   74261篇
  1989年   71463篇
  1988年   66416篇
  1987年   65239篇
  1986年   61665篇
  1985年   58681篇
  1984年   44344篇
  1983年   37760篇
  1982年   22948篇
  1979年   41367篇
  1978年   29017篇
  1977年   24371篇
  1976年   22857篇
  1975年   23981篇
  1974年   29663篇
  1973年   28061篇
  1972年   26239篇
  1971年   24165篇
  1970年   22761篇
  1969年   21101篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
942.
943.
Background: t(14; 18)/bcl-2 gene rearrangement (R) is claimedto impart a worse rate of complete remission and disease-freesurvival in diffuse large cell lymphoma (DLCL). DEL 6q has alsobeen associated with poor outcome. Design: Retrospective studyof 54 patients with either diffuse large cell or immunoblasticlymphoma who had cytogenetics and/or molecular studies performed.Results: Patient characteristics, complete remission rate, andtime to treatment failure (TTF) were similar at three year follow-upfor groups with and without t(14; 18)/BCL-2R Survival was worsefor the former but the difference was not statistically significant.For DEL 6q, patient characteristics and survival rates weresimilar at three year follow-up for patients with and withoutthe abnormality. TTF was worse for the former but this was notstatistically significant. Conclusion: This study, with equalor greater number of patients with t(14; 18) than previous reports,fails to show a worse prognosis for patients with the t(14;18) chromosomal abnormality. A definite association will awaitfurther accrual of patients and a meaningul multivariate analysis. lymphoma, BCL-2, cytogenetics, DEL 6q  相似文献   
944.
Using indirect immunohistochemistry and an antiserum raised against rat corticotrophin-releasing factor (CRF) we have outlined an asymmetric network of cells and varicose fibers in sheep adrenal cortex. This network was not associated with the larger splanchnic nerves, but was occasionally found in small bundles or with blood vessels; in most instances fibers were found weaving independently through cortical parenchyma. A plexus of fibers was found in the zona reticularis, with a few fibers ramifying into adjacent medulla. Uni or bipolar cells were found throughout the cortex, with the greatest frequency at the corticomedullary junction; a multipolar-type cell was also found in this area. Staining of varicose structures and most cells was abolished by incubation with excess rat CRF 1-41, but not by ovine CRF or a range of other peptides. Though the immunoreactive species has not as yet been identified, it may thus share homology with sequences present in rat but not ovine CRF.  相似文献   
945.
946.
In an attempt to identify a cause for the alteration in breathing pattern seen when conventional respiratory apparatus is applied to the face, we have studied the effects of causing the subject to focus attention on breathing by counting breaths in threes for 5 min. We used the respiratory inductance plethysmograph in 18 naive subjects who were unaware that their breathing was being measured. In the control periods, distraction was provided by a recorded story played through head-phones. The experiment was repeated with the rim of a facemask applied to the face. Focusing attention on breathing caused a prolongation of inspiration at a constant mean inspiratory flow, and lengthening of expiration. Tidal volume but not ventilation was increased. The facemask rim caused no significant change. It is concluded that conscious awareness of breathing could account for a major part of the effect of conventional respiratory apparatus.  相似文献   
947.
An epidemiologic study of coeliac disease in a geographically defined area of Sweden showed that the prevalence was 95.5/10(5) inhabitants aged 15 years or more. The highest prevalence, 178/10(5) inhabitants, was found in the age group 65-74 years. The lowest prevalence, 39/10(5) inhabitants, was found in patients aged 15-24 years. Among the associated diseases an especially high incidence of associated thyroid disease was observed: thyrotoxicosis occurred in 5.0% and hypothyroidism in 5.8% of the patients.  相似文献   
948.
In any case of acute bronchoconstriction the possibility of an adverse reaction to a drug should be considered. In many of such side reactions no allergic mechanism can be detected. Therefore, they are included into the category of pseudoallergic reactions (PAR). The clinically most important form of drug-induced bronchial asthma, analgesics asthma, belongs to this PAR group. A further risk for asthmatics are intravenous applications of contrast-media for roentgenography which in about 15% induce a severe, sometimes life-threatening pseudo-allergic adverse reaction. In asthmatics, the application of any beta-receptor blocking agents and also the use of parasympathicotonic eye drops for treatment of glaucoma are contraindicated. Paradoxical bronchial constriction following application of antiasthmatics are preponderantly caused by locally irritative actions, less frequently by genuine allergic phenomena or additive intolerance. The most reliable prophylaxis against drug-induced bronchial asthma consists in strong avoidance of all derivatives possibly capable to trigger any intolerance. A respective warning should entered into the emergency passport.  相似文献   
949.
Despite growing concern with rural elderly populations, little attention has focused on their mental health, ways it may correlate with physical health, or how rural mental health patterns compare to urban. Popular wisdom contends that elderly people in general, and rural elderly persons in particular, are at increased risk for mental illness. This article examines these questions. A review of available literature suggests that elderly people may be at only slightly greater risk of mental illness than the population at large, though there are some indications that rates of depression may be somewhat higher among the elderly population. Much of this same literature implies that objective environmental conditions play a significant role in the incidence of depression. Analysis of data gathered in a statewide random poll (N = 743) indicates that while physical health tends to be poorer among rural populations, when health is held constant there is actually an inverse relationship between age and depression. Therefore, rural elderly persons are no more likely to be depressed than their urban counterparts despite harsher living conditions. Both conceptual and policy implications are discussed.  相似文献   
950.
Brain tissues from 38 patients with a clinical suspicion of encephalitis or encephalopathy were examined by two immunoenzymatic techniques for the detection of arboviral antigen. Group B arboviral antigen was identified in 23 of these tissues. This simple method could be used for the diagnosis of the causal agent of encephalitis.  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