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   8867篇
  免费   817篇
  国内免费   51篇
耳鼻咽喉   55篇
儿科学   249篇
妇产科学   159篇
基础医学   1134篇
口腔科学   131篇
临床医学   995篇
内科学   1812篇
皮肤病学   94篇
神经病学   669篇
特种医学   479篇
外科学   1622篇
综合类   212篇
一般理论   26篇
预防医学   869篇
眼科学   73篇
药学   575篇
中国医学   52篇
肿瘤学   529篇
  2023年   55篇
  2022年   60篇
  2021年   126篇
  2020年   121篇
  2019年   176篇
  2018年   203篇
  2017年   148篇
  2016年   163篇
  2015年   164篇
  2014年   242篇
  2013年   356篇
  2012年   529篇
  2011年   512篇
  2010年   285篇
  2009年   277篇
  2008年   490篇
  2007年   472篇
  2006年   409篇
  2005年   449篇
  2004年   388篇
  2003年   333篇
  2002年   323篇
  2001年   239篇
  2000年   257篇
  1999年   211篇
  1998年   120篇
  1997年   110篇
  1996年   128篇
  1995年   99篇
  1994年   127篇
  1993年   94篇
  1992年   130篇
  1991年   159篇
  1990年   113篇
  1989年   137篇
  1988年   156篇
  1987年   178篇
  1986年   146篇
  1985年   126篇
  1984年   83篇
  1983年   70篇
  1982年   51篇
  1981年   45篇
  1980年   55篇
  1979年   69篇
  1978年   48篇
  1977年   58篇
  1976年   44篇
  1975年   45篇
  1974年   49篇
排序方式: 共有9735条查询结果,搜索用时 15 毫秒
91.
In a cross-sectional study of aggression, and adaptive and maladaptive behaviour in 128 subjects with Down's syndrome (DS), 29 of whom had dementia, the current authors found that the presence of dementia was not predictive of aggression or maladaptive behaviour. However, the level of adaptive behaviour was shown to be lower in subjects with dementia, and in those with lower levels of cognitive functioning, as measured on a rating instrument, the Test for Severe Impairment. Although the presence of aggressive behaviours is not higher in subjects with dementia and DS on cross-sectional review, it remains to be seen whether aggression will increase in individual cases with the onset or progression of dementia. The decline in adaptive behaviour shown in the present study confirms the findings of previous studies and indicates a direction for service development for persons with the dual diagnosis of dementia and DS.  相似文献   
92.
We leveraged genetic variants associated with caffeine metabolism in the two-sample Mendelian randomization framework to investigate the effect of plasma caffeine levels on the risk of Alzheimer’s disease and Parkinson’s disease. Genetic association estimates for the outcomes were obtained from the International Genomics of Alzheimer’s Project, the International Parkinson’s Disease Genomics consortium, the FinnGen consortium, and the UK Biobank. Genetically predicted higher plasma caffeine levels were associated with a non-significant lower risk of Alzheimer’s disease (odds ratio 0.87; 95% confidence interval 0.76, 1.00; p = 0.056). A suggestive association was observed for genetically predicted higher plasma caffeine levels and lower risk of Parkinson’s disease in the FinnGen consortium. but not in the International Parkinson’s Disease Genomics consortium; no overall association was found (odds ratio 0.92; 95% confidence interval 0.77, 1.10; p = 0.347). This study found possible suggestive evidence of a protective role of caffeine in Alzheimer’s disease. The association between caffeine and Parkinson’s disease requires further study.  相似文献   
93.
(1) Background: The aim of this study was to evaluate the effectiveness of a three-component nutrition, sleep, and physical activity (PA) program on cardiorespiratory fitness, body composition, and health behaviors in overweight airline pilots. (2) Methods: A parallel group study was conducted amongst 125 airline pilots. The intervention group participated in a 16-week personalized healthy eating, sleep hygiene, and PA program. Outcome measures of objective health (maximal oxygen consumption (VO2max), body mass, skinfolds, girths, blood pressure, resting heart rate, push-ups, plank hold) and self-reported health (weekly PA, sleep quality and duration, fruit and vegetable intake, and self-rated health) were collected at baseline and post-intervention. The wait-list control completed the same assessments. (3) Results: Significant group main effects in favor of the intervention group were found for all outcome measures (p < 0.001) except for weekly walking (p = 0.163). All objective health measures significantly improved in the intervention group when compared to the control group (p < 0.001, d = 0.41–1.04). Self-report measures (moderate-to-vigorous PA, sleep quality and duration, fruit and vegetable intake, and self-rated health) significantly increased in the intervention group when compared to the control group (p < 0.001, d = 1.00–2.69). (4) Conclusion: Our findings demonstrate that a personalized 16-week healthy eating, PA, and sleep hygiene intervention can elicit significant short-term improvements in physical and mental health outcomes among overweight airline pilots. Further research is required to examine whether the observed effects are maintained longitudinally.  相似文献   
94.
95.
This article provides a comprehensive literature review regarding side effects both minor and major associated with contrast agent injection. This includes a discussion of nephrogenic systemic fibrosis (NSF), which remains highly topical. Radiographers now commonly are responsible for injection of contrast agent in patients, in keeping with their extended role. Therefore it is incumbent on them to understand the agents they inject, the contra-indications for injection and any potential associated risks, so that they can act and react accordingly in a timely manner. The need for this knowledge was made very evident after the recent death of a patient from anaphylactic shock when there was a delay in mounting the appropriate procedure. This paper represents a synthesis of relevant articles and reflects on the results, before drawing appropriate conclusions particularly those of special relevance to radiographers.  相似文献   
96.
The research-related performance of universities, as well as that of individual researchers, is increasingly evaluated through the use of objective measures, or metrics, which seek to support or in some cases even replace more traditional methods of peer review. In particular there is a growing awareness in research communities, government organisations and funding bodies around the concept of using evaluation metrics to analyse research citations. The tools available for ‘citation analysis’ are many and varied, enabling a quantification of scientific quality, academic impact and prestige. However there is increasing concern regarding the potential misuse of such tools, which have limitations in certain research disciplines.This article uses ‘real world’ examples from radiography research and scholarship to illustrate the range of currently available citation analysis tools. It explores the academic debate surrounding their strengths and limitations, and identifies the potential impact of citation analysis on the radiography research community.The article concludes that citation analysis is a valuable tool for researchers to use for personal reflection and research planning, yet there are inherent dangers if it is used inappropriately. Whilst citation analysis can give objective information regarding an individual, research group, journal or higher education institution, it should not be used as a total substitute for traditional qualitative review and peer assessment.  相似文献   
97.
98.
99.
100.
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