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   1163篇
  免费   202篇
  国内免费   18篇
耳鼻咽喉   12篇
儿科学   49篇
妇产科学   12篇
基础医学   92篇
口腔科学   12篇
临床医学   230篇
内科学   310篇
皮肤病学   32篇
神经病学   62篇
特种医学   81篇
外科学   223篇
综合类   56篇
现状与发展   20篇
一般理论   1篇
预防医学   80篇
眼科学   27篇
药学   32篇
中国医学   2篇
肿瘤学   50篇
  2024年   7篇
  2023年   42篇
  2021年   22篇
  2020年   25篇
  2019年   13篇
  2018年   51篇
  2017年   45篇
  2016年   33篇
  2015年   47篇
  2014年   47篇
  2013年   64篇
  2012年   32篇
  2011年   43篇
  2010年   56篇
  2009年   70篇
  2008年   46篇
  2007年   34篇
  2006年   41篇
  2005年   22篇
  2004年   18篇
  2003年   20篇
  2002年   29篇
  2001年   26篇
  2000年   26篇
  1999年   26篇
  1998年   36篇
  1997年   40篇
  1996年   44篇
  1995年   31篇
  1994年   19篇
  1993年   26篇
  1992年   12篇
  1991年   16篇
  1990年   16篇
  1989年   18篇
  1988年   21篇
  1987年   23篇
  1986年   19篇
  1985年   23篇
  1984年   7篇
  1983年   11篇
  1982年   11篇
  1981年   13篇
  1980年   7篇
  1978年   13篇
  1977年   13篇
  1976年   11篇
  1975年   8篇
  1971年   6篇
  1960年   6篇
排序方式: 共有1383条查询结果,搜索用时 15 毫秒
81.
82.

Background  

Anxiety and depression co-occur in children and adolescents with anxiety commonly preceding depression. Although there is some evidence to suggest that the association between early anxiety and later depression is explained by a shared genetic aetiology, the contribution of environmental factors is less well examined and it is unknown whether anxiety itself is a phenotypic risk factor for later depression. These explanations of the association between early anxiety and later depression were evaluated.  相似文献   
83.
OBJECTIVE: To establish risk factor causal associations for coronary artery disease (CAD) in the native Pakistani population. METHODS: We conducted a hospital-based, case-control study of 200 cases with angiographically documented CAD and 200 age- and sex-matched controls without angiographic evidence of CAD. Patients on lipid lowering therapy were excluded. Lifestyle, anthropometric and biochemical risk factors were assessed in both groups. RESULTS: The presence of CAD was associated with current, past or passive smoking, a history of diabetes and high blood pressure, a positive family risk factors in this study; levels were below history of CAD, body fat percentage, waist-hip ratio (WHR), low apolipoprotein A1 or low HDL, lipoprotein (a), glucose, insulin, insulin resistance, C-reactive protein (CRP), total cholesterol to HDL ratio (TC/HDL) and creatinine on univariate conditional logistic regression analysis. In multiple regression analysis, significant independent associations were found with low HDL (OR 0.11; 95% CI 0.04-0.34; p < 0.001) positive family history (OR 1.79; 95% CI 1.09-2.93; p = 0.02), CRP (OR 1.45; 95% CI 1.19-1.75; p < 0.001) and WHR (OR 1.04; 95% CI 1.01-1.08; p = 0.01). Angiograms were also quantified for the extent and severity of CAD by the Gensini scoring system. Quantitative angiographic data showed associations with age (p = 0.01), the duration of diabetes (p = 0.04), WHR (p = 0.06), low HDL (p < 0.001), lipoprotein (a) (p = 0.001), creatinine (p < 0.001) and CRP (p = 0.007). Results indicate that total and LDL cholesterol were not significant currently accepted thresholds for treatment. CONCLUSIONS: The cardiovascular risk profile in this population is consistent with metabolic syndrome where low HDL and WHR can be used to predict the risk of CAD. Results suggest the need to redefine the currently practised approach to CAD management in this population to fit local needs.  相似文献   
84.
Lumb AB  Vail A 《Medical education》2004,38(9):1002-1005
OBJECTIVES: To compare the relative importance of social, academic and application form factors at admission in predicting performance in the first 3 years of a medicine course. DESIGN: Retrospective cohort study. SETTING: A single UK medical school. PARTICIPANTS: A total of 738 students who entered medical school between 1994 and 1997. MAIN OUTCOME MEASURE: Performance in Year 3 objective structured clinical examination (OSCE). RESULTS: School-leaving grades were significant predictors of success in the OSCE. Non-academic activities as assessed from the application form were associated with poorer performance. Mature students performed extremely well, and male and ethnic minority students performed less well. Socioeconomic status and type of school attended were not found to affect performance on the course. CONCLUSIONS: The relatively poor performance of male and ethnic minority students urgently needs further investigation. Our results carry no suggestion that, other things being equal, widening access to medical school for mature students and those from less affluent backgrounds would result in poorer performance.  相似文献   
85.
New aspects of ventilation in acute lung injury   总被引:8,自引:0,他引:8  
Malarkkan N  Snook NJ  Lumb AB 《Anaesthesia》2003,58(7):647-667
Recent recognition that artificial ventilation may cause damage to the acutely injured lung has caused renewed interest in ventilation techniques that minimise this potential harm. Many ventilation techniques have proved beneficial in small trials of very specific patient groups, but most have subsequently failed to translate into improved patient outcome in larger trials. An exception to this is 'protective ventilation' using reduced tidal volumes (to lower airway pressure) and increased PEEP (to reduce pulmonary collapse). Results of trials of protective ventilation have been encouraging, and the technique should now be adopted more widely. High frequency ventilation, inverse ratio ventilation, prone positioning and inhaled nitric oxide are all techniques that may be considered when, in spite of optimal artificial ventilation, the patient's gas exchange remains dangerously poor. Under these circumstances, the choice of technique is dependent on their availability, local expertise and individual patient needs.  相似文献   
86.
The clinical and biochemical determinants of the fibrinogen response to simvastatin or atorvastatin therapy were assessed in 130 patients with severe polygenic or familial hypercholesterolemia treated in a randomized open-trial format design. Hyperfibrinogenemia was associated with atorvastatin, baseline fibrinogen, and initial concentration and change in concentration of apolipoprotein B or low-density lipoprotein cholesterol.  相似文献   
87.
88.
BACKGROUND: Plasma homocysteine and the methylene tetrahydrofolate reductase C677T polymorphism have been suggested as being risk factors for cardiovascular disease. OBJECTIVE: To determine whether plasma homocysteine and the methylene tetrahydrofolate reductase C677T polymorphism are risk factors for coronary heart disease in patients with heterozygous familial hypercholesterolaemia as compared with those with polygenic hyperlipidaemia. METHODS: Plasma homocysteine and the methylene tetrahydrofolate reductase polymorphism were assessed with other risk factors in 112 patients with familial hypercholesterolaemia and 72 patients with polygenic hyperlipidaemia, of whom 29 (25.8%) and 30 (41%) respectively had established cardiovascular disease and in 100 healthy normal subjects. RESULTS: Plasma homocysteine was not significantly elevated in patients with and without coronary heart disease with familial hypercholesterolaemia or polygenic hyperlipidaemia compared with controls. The allele frequencies for C677T were significantly different in patients with coronary heart disease and with polygenic hyperlipidaemia (0.35 versus 0.29) (P = 0.02) as opposed to those with coronary heart disease and familial hypercholesterolaemia (0.25 versus 0.30) (P = 0.63). Methylene tetrahydrofolate reductase genotype but not homocysteine had a weak association with coronary heart disease in logistic regression analysis in patients with polygenic hyperlipidaemia (P = 0.05) but neither methylene tetrahydrofolate reductase genotype or plasma homocysteine was a risk factor in patients with familial hypercholesterolaemia. CONCLUSION: Whilst methylene tetrahydrofolate reductase genotype may be a weak risk factor for coronary heart disease in polygenic hyperlipidaemia as opposed to familial hypercholesterolaemia, homocysteine does not seem to be an important risk factor for coronary heart disease in patients in southern UK.  相似文献   
89.
90.
盐酸放线瑞香宁(actinodaphine-HCl)系从莲叶桐科青藤属植物黑吹风(Illigera khasiana C.B Clarke)中分离提取而得的有效成分,结构式如图1。药理试验证明有解热、镇痛、解痉等作用。本文报告用紫外二阶导数光谱法研究盐酸放线瑞香宁在兔体内的药代动力学结果。家兔4只,体重2.8±0.6kg。盐酸放线瑞香宁由本所植化室提供。氯仿、乙醇均为A.R。Perkin-Elmer型紫外—可见光分光光度计系美国产品。  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