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   491篇
  免费   29篇
  国内免费   18篇
耳鼻咽喉   7篇
儿科学   19篇
妇产科学   8篇
基础医学   23篇
口腔科学   21篇
临床医学   62篇
内科学   108篇
皮肤病学   8篇
神经病学   16篇
特种医学   48篇
外科学   102篇
综合类   12篇
预防医学   21篇
眼科学   3篇
药学   39篇
肿瘤学   41篇
  2023年   3篇
  2022年   6篇
  2021年   4篇
  2020年   3篇
  2019年   8篇
  2018年   13篇
  2017年   15篇
  2016年   8篇
  2015年   10篇
  2014年   20篇
  2013年   22篇
  2012年   21篇
  2011年   20篇
  2010年   29篇
  2009年   20篇
  2008年   31篇
  2007年   33篇
  2006年   21篇
  2005年   11篇
  2004年   19篇
  2003年   11篇
  2002年   4篇
  2001年   9篇
  2000年   8篇
  1999年   9篇
  1998年   14篇
  1997年   13篇
  1996年   16篇
  1995年   10篇
  1994年   14篇
  1993年   12篇
  1992年   4篇
  1991年   10篇
  1990年   3篇
  1989年   9篇
  1988年   13篇
  1987年   7篇
  1986年   10篇
  1985年   14篇
  1984年   5篇
  1983年   5篇
  1982年   5篇
  1981年   2篇
  1980年   3篇
  1979年   1篇
  1978年   3篇
  1977年   2篇
  1976年   2篇
  1975年   3篇
排序方式: 共有538条查询结果,搜索用时 642 毫秒
91.
92.
93.
94.
Objective: Globally, depression is one of the most prevalent and burdensome conditions in older adults. However, there are few population-based studies of depression in older adults in developing countries. In this paper, we examine the prevalence of depressive symptoms and explore possible contributory risk factors in older adults living in Nepal.

Methods: A cross-sectional study was conducted in two semi-urban communities in Kathmandu, Nepal. Depression was assessed using the 15-item Geriatric Depression Scale in 303 participants, aged 60 years and over. Multivariate logistic regression was then used to assess associations between potential risk factors and depression.

Results: More than half of the participants (n = 175, 60.6%) had significant depressive symptomatology, with 27.7% having scores suggesting mild depression. Illiteracy (aOR = 2.01, 95% CI: 1.08–3.75), physical immobility (aOR = 5.62, 95% CI: 1.76–17.99), the presence of physical health problems (aOR = 1.97, 95% CI: 1.03–3.77), not having any time spent with family members (aOR = 3.55, 95% CI: 1.29–9.76) and not being considered in family decision-making (aOR = 4.02, 95% CI: 2.01–8.04) were significantly associated with depression in older adults.

Conclusion: The prevalence of depression was significant in older adults. There are clear associations of depression with demographic, social support and physical well-being factors in this population. Strategies that increase awareness in the community along with the health and social care interventions are needed to address the likely drivers of depression in older adults.  相似文献   

95.
96.
97.
Cough etiquette and respiratory hygiene are forms of source control encouraged to prevent the spread of respiratory infection. The use of surgical masks as a means of source control has not been quantified in terms of reducing exposure to others. We designed an in vitro model using various facepieces to assess their contribution to exposure reduction when worn at the infectious source (Source) relative to facepieces worn for primary (Receiver) protection, and the factors that contribute to each. In a chamber with various airflows, radiolabeled aerosols were exhaled via a ventilated soft-face manikin head using tidal breathing and cough (Source). Another manikin, containing a filter, quantified recipient exposure (Receiver). The natural fit surgical mask, fitted (SecureFit) surgical mask and an N95-class filtering facepiece respirator (commonly known as an “N95 respirator”) with and without a Vaseline-seal were tested. With cough, source control (mask or respirator on Source) was statistically superior to mask or unsealed respirator protection on the Receiver (Receiver protection) in all environments. To equal source control during coughing, the N95 respirator must be Vaseline-sealed. During tidal breathing, source control was comparable or superior to mask or respirator protection on the Receiver. Source control via surgical masks may be an important adjunct defense against the spread of respiratory infections. The fit of the mask or respirator, in combination with the airflow patterns in a given setting, are significant contributors to source control efficacy. Future clinical trials should include a surgical mask source control arm to assess the contribution of source control in overall protection against airborne infection.  相似文献   
98.
99.
100.

Introduction

Mammographic density is known to be a strong risk factor for breast cancer. A particularly strong association with risk has been observed when density is measured using interactive threshold software. This, however, is a labour-intensive process for large-scale studies.

Methods

Our aim was to determine the performance of visually assessed percent breast density as an indicator of breast cancer risk. We compared the effect on risk of density as measured with the mediolateral oblique view only versus that estimated as the average density from the mediolateral oblique view and the craniocaudal view. Density was assessed using a visual analogue scale in 10,048 screening mammograms, including 311 breast cancer cases diagnosed at that screening episode or within the following 6 years.

Results

Where only the mediolateral oblique view was available, there was a modest effect of breast density on risk with an odds ratio for the 76% to 100% density relative to 0% to 25% of 1.51 (95% confidence interval 0.71 to 3.18). When two views were available, there was a considerably stronger association, with the corresponding odds ratio being 6.77 (95% confidence interval 2.75 to 16.67).

Conclusion

This indicates that a substantial amount of information on risk from percentage breast density is contained in the second view. It also suggests that visually assessed breast density has predictive potential for breast cancer risk comparable to that of density measured using the interactive threshold software when two views are available. This observation needs to be confirmed by studies applying the different measurement methods to the same individuals.  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