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   14454篇
  免费   1800篇
  国内免费   296篇
耳鼻咽喉   58篇
儿科学   157篇
妇产科学   120篇
基础医学   1301篇
口腔科学   194篇
临床医学   1282篇
内科学   1308篇
皮肤病学   112篇
神经病学   751篇
特种医学   537篇
外科学   1002篇
综合类   2342篇
现状与发展   2篇
一般理论   8篇
预防医学   3935篇
眼科学   269篇
药学   1694篇
  8篇
中国医学   917篇
肿瘤学   553篇
  2024年   87篇
  2023年   470篇
  2022年   724篇
  2021年   1060篇
  2020年   932篇
  2019年   808篇
  2018年   703篇
  2017年   723篇
  2016年   647篇
  2015年   603篇
  2014年   1045篇
  2013年   1169篇
  2012年   690篇
  2011年   803篇
  2010年   605篇
  2009年   549篇
  2008年   614篇
  2007年   609篇
  2006年   564篇
  2005年   458篇
  2004年   405篇
  2003年   348篇
  2002年   277篇
  2001年   190篇
  2000年   142篇
  1999年   114篇
  1998年   117篇
  1997年   112篇
  1996年   80篇
  1995年   68篇
  1994年   82篇
  1993年   68篇
  1992年   60篇
  1991年   58篇
  1990年   50篇
  1989年   61篇
  1988年   45篇
  1987年   53篇
  1986年   40篇
  1985年   48篇
  1984年   44篇
  1983年   33篇
  1982年   42篇
  1981年   25篇
  1980年   39篇
  1979年   15篇
  1978年   13篇
  1977年   13篇
  1976年   15篇
  1974年   8篇
排序方式: 共有10000条查询结果,搜索用时 484 毫秒
51.
Arrays with large numbers of independent coil elements are becoming increasingly available as they provide increased signal-to-noise ratios (SNRs) and improved parallel imaging performance. Processing of data from a large set of independent receive channels is, however, associated with an increased memory and computational load in reconstruction. This work addresses this problem by introducing coil array compression. The method allows one to reduce the number of datasets from independent channels by combining all or partial sets in the time domain prior to image reconstruction. It is demonstrated that array compression can be very effective depending on the size of the region of interest (ROI). Based on 2D in vivo data obtained with a 32-element phased-array coil in the heart, it is shown that the number of channels can be compressed to as few as four with only 0.3% SNR loss in an ROI encompassing the heart. With twofold parallel imaging, only a 2% loss in SNR occurred using the same compression factor.  相似文献   
52.
A fundamental prerequisite of population health research is the ability to establish an accurate denominator. This in turn requires that every individual in the study population is counted. However, this seemingly simple principle has become a point of conflict between researchers whose aim is to produce evidence of disparities in population health outcomes and governments whose policies promote (intentionally or not) inequalities that are the underlying causes of health disparities. Research into the health of asylum seekers is a case in point. There is a growing body of evidence documenting the adverse affects of recent changes in asylum-seeking legislation, including mandatory detention. However, much of this evidence has been dismissed by some governments as being unsound, biased and unscientific because, it is argued, evidence is derived from small samples or from case studies. Yet, it is the policies of governments that are the key barrier to the conduct of rigorous population health research on asylum seekers. In this paper, the authors discuss the challenges of counting asylum seekers and the limitations of data reported in some industrialized countries. They argue that the lack of accurate statistical data on asylum seekers has been an effective neo-conservative strategy for erasing the health inequalities in this vulnerable population, indeed a strategy that renders invisible this population. They describe some alternative strategies that may be used by researchers to obtain denominator data on hard-to-reach populations such as asylum seekers.  相似文献   
53.
研究医院HIS系统中药品数据的异地存储技术。利用Mobilink同步技术,实现Microsoft SQL Server统一数据库和Adaptive ServerAnywhere远程数据库之间的数据同步。  相似文献   
54.
This paper provides new evidence on the degree of income-related inequality in self-assessed health in Belgium. First of all, we combine the time dimension, which has been shown to be very important in the analysis of inequality, and the use of the recently developed interval regression approach to transform a categorical health variable in a continuous one. Second, we measure how the long-run inequality differs from the short-run inequality. Finally, we decompose this health-related income mobility index as well as the long-run concentration index (CI) itself into its contributors. Using data from the panel survey of Belgian households (1994–2002), we find that health is pro-rich distributed and that its inequality is underestimated by 9.45% when neglecting the dynamics of individuals over time. Income, education, job status and age are the most important contributors in the CI and the difference between the short-run and long-run inequality.   相似文献   
55.
根据1022例新鲜胎尸的不同受精龄与体重,十项重要器官(心、肝、脾、左右肺、左右肾、左右肾上腺、胸腺等)的重量进行测量,将所测得的原始数据输入到IBM-PC/XT微型计算机内进行数据处理。探讨胎儿生长发育的基本规律。结果:(1)建立了胎儿体重与胎龄之间的推算式;(2)建立了胎儿各重要器官重量与胎龄之间的推算式;(3)建立了胎儿体重每月平均增长量与胎龄之间的推算式;(4)按胎儿体重每月平均增长量,用有序聚类分析方法,将胎儿生长发育过程划分为三个阶段。  相似文献   
56.
①目的研究影响青岛市城乡居民选择就诊单位的因素。②方法采用多项式Logistic回归分析法,分析影响青岛市城乡居民选择就诊单位的主要因素。③结果影响市区病人选择就诊单位的主要因素是医疗保健制度和居民健康状况.农村病人的主要影响因素是家庭收入、健康状况和受教育程度。④结论居民就诊单位选择受多种因素的影响,建议加快医疗保健制度的改革.完善医疗保健制度。  相似文献   
57.
Telemetry of programmed and measured data is an important feature of many pacemakers currently used in clinical practice. The ability to receive non-invasive data from the implanted device constitutes a major advantage for the long-term follow-up of the patients and of device performance. There are numerous types of data retrievable via telemetry: parameters of device characteristics (output, battery longevity, impedance, etc), event recorders or counters, event markers, and endocardial electrograms. Ideally, this information should be beneficial in the longitudinal surveilance of modern pacemakers.  相似文献   
58.
59.
Objective — To study the validity and accuracy of an adjusted questionnaire on medical drug use during pregnancy eight years after the pregnancy. Methods — The ability of a questionnaire on medication during pregnancy to detect actual use (= sensitivity) was tested against information collected 8 years previously (in 1983–1984) from 473 women with high-risk pregnancies who delivered at the University Hospital Nijmegen, the Netherlands. Results — For separate drug groups, the sensitivity varied between 5% and 91%. The timing of use was recalled moderately well. Although specific questions on drug groups did improve the sensitivity as compared to an earlier questionnaire, the improvement was not enough to make the questionnaire valid. High maternal education, low birth weight, low gestational age and a low 5-min Apgar score were related to better recall. The sensitivity of the questionnaire depended on the behavioural score of the child, implying recall bias. Conclusion — Questionnaire data on drug use during pregnancy obtained eight years after delivery are not a valid source of information.  相似文献   
60.
I contend that although the Luborsky et al. findings on the Dodo bird verdict are noteworthy, the methodology on which they are based is significantly delimited. Amplifying Luborsky et al.'s moderate recognition of that delimitation, I propose a qualitative complement to the extant research. I call this complement "amalgamated" qualitative research and propose that it will deepen, clarify, and contextualize Luborsky et al.'s enigmatic findings. Until this amalgam is implemented, therapy research will be relegated to impressions rather than fine-grained illuminations.  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