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   4935篇
  免费   225篇
  国内免费   86篇
耳鼻咽喉   63篇
儿科学   227篇
妇产科学   53篇
基础医学   391篇
口腔科学   103篇
临床医学   627篇
内科学   807篇
皮肤病学   81篇
神经病学   514篇
特种医学   137篇
外科学   806篇
综合类   382篇
预防医学   413篇
眼科学   113篇
药学   247篇
中国医学   132篇
肿瘤学   150篇
  2024年   7篇
  2023年   157篇
  2022年   241篇
  2021年   333篇
  2020年   262篇
  2019年   313篇
  2018年   281篇
  2017年   178篇
  2016年   160篇
  2015年   123篇
  2014年   388篇
  2013年   347篇
  2012年   181篇
  2011年   308篇
  2010年   202篇
  2009年   235篇
  2008年   229篇
  2007年   203篇
  2006年   166篇
  2005年   143篇
  2004年   95篇
  2003年   71篇
  2002年   59篇
  2001年   70篇
  2000年   64篇
  1999年   53篇
  1998年   44篇
  1997年   30篇
  1996年   30篇
  1995年   23篇
  1994年   24篇
  1993年   13篇
  1992年   18篇
  1991年   16篇
  1990年   19篇
  1989年   18篇
  1988年   17篇
  1987年   13篇
  1986年   13篇
  1985年   16篇
  1984年   14篇
  1983年   8篇
  1982年   11篇
  1981年   8篇
  1980年   8篇
  1979年   7篇
  1978年   6篇
  1977年   8篇
  1975年   3篇
  1972年   6篇
排序方式: 共有5246条查询结果,搜索用时 78 毫秒
41.
慢性阻塞性肺疾病(以下简称慢阻肺)是一种常见的慢性气道异质性疾病。近年来,尽管国内外慢阻肺相关研究不断深入,管理日趋完善,但仍有许多难点亟待解决。2022年9月,《柳叶刀》杂志发布《消除慢阻肺之路》,该文件针对慢阻肺的认识、诊断、评估和个体化治疗等方面提出了新理念并提供临床诊疗指导。本文重点对该文件中慢阻肺的分类、诊断标准及诊断建议、慢阻肺的急性加重和迈向消除慢阻肺5个方面进行介绍和解读,以期为我国临床工作者开展慢阻肺相关研究和管理提供一定的参考及启示。  相似文献   
42.
The zurich study     
Summary This study describes sleep behaviour and insomnia in a representative cohort of a Swiss population. Interviews were carried out prospectively from age 20–21 to 27–28 years, starting with 292 males and 299 females. Females usually go to bed earlier and sleep 30 min longer than males. Taking into account length and periodicity of insomnia we can distinguish occasional insomnia (OI), repeated brief insomnia (RBI), and continued insomnia (CI), defined by operational criteria. The prevalence of sleep problems is stable from age 21–28, at 36%–40%. CI (prevalence 8%–10%) and RBI (13%–19%) are both medical problems in terms of treatment by professionals (10%–17%) or self-medication (7%–12%). The majority of insomniacs cope with sleep problems in various other ways. Frequency and patterns of symptoms of insomnia are described.The authors thank P. J. Clayton, M.D., University of Minnesota, Minneapolis, for advice and critical suggestions and for the coining of the terms repeated brief insomnia and continued insomnia.Project supported by grant 3.948.0.85 from the Swiss National Science Foundation.Parts of this article were presented on the occasion of the inauguration ceremony of the Department of Psychiatry of the University of Mainz on April 2 and 3, 1987  相似文献   
43.
Current European Community (Annex V) guidelines recommend the use of 20 test animals in the guinea pig maximisation test for skin sensitisation. The suitability, for classification and labelling purposes, of reducing the number of test animals has been examined by analysing the results of 40 studies submitted to the Health and Safety Executive, and by the use of a mathematical model. Our results suggest that in most cases an experiment with ten test animals can be used to determine satisfactorily whether a substance should be labelled with the risk phrase may cause sensitisation by skin contact. However, serious consideration should be given to the need for additional investigation if two or three of the ten test animals show a sensitisation response. The highest nonirritant concentration of a substance should be used at challenge. Clearer guidance in Annex V on evaluating challenge responses would be beneficial.  相似文献   
44.
Summary In five patients single or multiple glucagonomas were characterized by immunocytochemistry. Two large single glucagonomas were associated with the glucagonoma syndrome, which completely dissappeared after removal of the tumours. The morphologic findings in these patients are compared with 48 others collected from literature.In the other three patients, the glucagonomas were not associated with a clinical syndrome and were detected by chance (one accompanying an insulinoma; the other in pancreases of patients suffering from multiple endocrine neoplasia I; MEN I). These tumours appeared by their histological, immunocytochemical and ultrastructural features better organized than the glucagonomas with syndrome.Glucagonomas not producing a syndrome can be classified into (a) solitary, often malignant endocrine pancreatic tumours, (b) glucagonomas associated with insulinomas and other tumours, (c) multiple glucagonomas in MEN I and (d) single microglucagonomas in elderly patients. It is emphasized that only immunohistology allows clear identification of these tumours as glucagonomas.  相似文献   
45.
The blind panel collected for the 8th Human Leucocyte Differentiation Antigens Workshop (HLDA8; ) included 49 antibodies of known CD specificities and 76 antibodies of unknown specificity. We have identified groups of antibodies showing similar patterns of reactivity that need to be investigated by biochemical methods to evaluate whether the antibodies within these groups are reacting with the same molecule. Our approach to data analysis was based on the work of Salganik et al. (in press) [Salganik, M.P., Milford E.L., Hardie D.L., Shaw, S., Wand, M.P., in press. Classifying antibodies using flow cytometry data: class prediction and class discovery. Biometrical Journal].  相似文献   
46.
Fuzzy rules to predict degree of malignancy in brain glioma   总被引:2,自引:0,他引:2  
The current pre-operative assessment of the degree of malignancy in brain glioma is based on magnetic resonance imaging (MRI) findings and clinical data. 280 cases were studied, of which 111 were high-grade malignancies and 169 were low-grade, so that regular and interpretable patterns of the relationships between glioma MRI features and the degree of malignancy could be acquired. However, as uncertainties in the data and missing values existed, a fuzzy rule extraction algorithm based on a fuzzy min-max neural network (FMMNN) was used. The performance of a multi-layer perceptron network (MLP) trained with the error back-propagation algorithm (BP), the decision tree algorithm ID3, nearest neighbour and the original fuzzy min-max neural network were also evaluated. The results showed that two fuzzy decision rules on only six features achieved an accuracy of 84.6% (89.9% for low-grade and 76.6% for high-grade cases). Investigations with the proposed algorithm revealed that age, mass effect, oedema, post-contrast enhancement, blood supply, calcification, haemorrhage and the signal intensity of the T1-weighted image were important diagnostic factors.  相似文献   
47.
Since its publication in 2001 the International Classification of Functioning, Disability and Health (ICF) has attracted debate about the content and the model presented. After almost 20 years use, regular updating since 2008 and with the prospect of a new edition in 2020 there is increasing interest in the ICF as a tool to meet contemporary information requirements. Information on functioning is important across not only health systems, but all areas where change in functioning is important: education, employment, and social welfare for example. This commentary responds to the issues raised in a commentary by Mitra & Shakespeare in 2019 and supports review of the ICF in the current context by informing users and providers of data on human functioning how they might engage in the maintenance, updating, and modernisation of the ICF.  相似文献   
48.
患者安全问题已经成为世界各国医疗质量管理关注的焦点,从国家层面对医疗质量安全不良事件进行统一定义和分类具有重要意义。通过总结世界卫生组织、美国、英国以及我国目前不良事件分类及严重程度分级情况,结合我国相关上报数据,分析存在问题,建议国家及各级卫生行政部门发挥引导推动作用,医疗机构利用现有国家医疗质量安全相关平台,参考借鉴相关分类,开展同质化医疗质量安全管理工作。  相似文献   
49.
目的:建立早期股骨头坏死塌陷风险评估预测体系,预测评估塌陷风险。方法:结合Steinberg分期、力学承载的ABC分型和近端硬化带比例建立早期股骨头坏死塌陷风险评估体系,首先应用Steinberg分期系统分期,Ⅰ期应用ABC分型预测风险,C型无风险,B型为低风险型,A型和BC型为中风险型,A-C和AB型为高风险型。SteinbergⅡ-Ⅲ分期首先进行硬化带分型,若为2型直接预测为低风险型;若为1型,则进一步进行ABC分型的划分,预测C型为无风险,B型为低风险型,A型和BC型为中风险型,A-C和AB型为高风险型。依据此预测体系应用回顾性分析的方法,预测由中国中医科学院广安门医院骨科门诊收集的188例(301髋)股骨头病例塌陷风险。并对3名医生及1名医生前后不同时间应用该体系预测结果的一致性进行评价。结果:188例(301髋)股骨头坏死病例。其中男136例,女52例;年龄19~64(42.61±12.07)岁;单髋75例,双髋113例;病程0.33~5.00(3.62±1.93)年。301髋病例中206髋发生塌陷(塌陷率68.44%)。无风险组,1髋中0髋发生塌陷,塌陷率0%;低风险组,91髋中9髋发生塌陷,塌陷率9.89%;中风险组,19髋中12髋发生塌陷,塌陷率63.16%;高风险组,190髋中185髋发生塌陷,塌陷率97.37%,不同风险组间差异有统计学意义(P=0.00)。该体系预测价值较高(ROC曲线AUC=0.95,P=0.00)。不同医生预测结果一致性良好(IC C=0.94,P=0.00),同一医生前后两次预测结果一致性良好(Kappa系数=0.90,P=0.00)。结论:早期股骨头坏死风险评估预测体系根据不同时期影像学特点选择不同方法预测塌陷风险,结合多风险因素综合评估,适用范围广泛,操作简捷,便于临床应用。  相似文献   
50.
Supracondylar humerus fractures are the most common fractures around the elbow in children between 4 and 10 years of age. The treatment of supracondylar humerus fractures can vary from conservative treatment to operative treatment depending on the fracture type. All around the world, the most commonly used classification system is the Wilkins-modified Gartland classification of supracondylar humerus fractures. Currently, the decision to operate or conserve the fracture is taken on basis of this classification system. Non-operative treatment for type I fractures and operative treatment for type III fractures have been well-established in literature. The management of type II supracondylar humerus fracture creates confusion in the minds of numerous orthopaedic surgeons around the world. We have tried addressing this using a classification-based treatment algorithm. Other classification systems like the AO classification, Lagrange and Rigault classification and Bahk classification with special reference to special fracture patterns that require attention and pre-op planning have also been mentioned. It is important to understand that operative management of each supracondylar humerus fracture is unique as regards fixation method and it is important to consider the fracture pattern before internal fixation.  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