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   214318篇
  免费   3325篇
  国内免费   225篇
耳鼻咽喉   1614篇
儿科学   7760篇
妇产科学   3965篇
基础医学   20422篇
口腔科学   2818篇
临床医学   15723篇
内科学   39322篇
皮肤病学   1432篇
神经病学   18680篇
特种医学   10239篇
外国民族医学   6篇
外科学   35863篇
综合类   3229篇
现状与发展   3篇
一般理论   34篇
预防医学   20710篇
眼科学   4173篇
药学   12511篇
  1篇
中国医学   931篇
肿瘤学   18432篇
  2023年   473篇
  2022年   1212篇
  2021年   1907篇
  2020年   1103篇
  2019年   1402篇
  2018年   23360篇
  2017年   18390篇
  2016年   20608篇
  2015年   2361篇
  2014年   2679篇
  2013年   2977篇
  2012年   10241篇
  2011年   24099篇
  2010年   20526篇
  2009年   12993篇
  2008年   21711篇
  2007年   23939篇
  2006年   2751篇
  2005年   4127篇
  2004年   5108篇
  2003年   5822篇
  2002年   3755篇
  2001年   669篇
  2000年   740篇
  1999年   463篇
  1998年   427篇
  1997年   349篇
  1996年   255篇
  1995年   219篇
  1994年   205篇
  1993年   149篇
  1992年   202篇
  1991年   253篇
  1990年   260篇
  1989年   206篇
  1988年   168篇
  1987年   140篇
  1986年   113篇
  1985年   155篇
  1984年   104篇
  1983年   85篇
  1982年   94篇
  1981年   64篇
  1980年   87篇
  1979年   56篇
  1978年   56篇
  1974年   58篇
  1938年   63篇
  1932年   57篇
  1930年   48篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Reactive oxygen metabolites (ROM) have been postulated to contribute to the development of various carcinomas, including colon cancer. Indeed, the effects of ROM scavengers are being tested for chemoprevention of adenocarcinoma of the colon. However, there has been no evidence to indicate that high levels of ROM are indeed present in cancerous tissue. In this study, we used a chemiluminescence probe to estimate ROM levels in cancerous and neighboring noncancerous colonic tissues from seven patients with colon cancer. Cancerous tissues contained significantly (p < 0.05) more luminol‐enhanced chemiluminescence (4,808 ± 2,282 counts/min/mg protein) than neighboring noncancerous tissues (2,175 ± 1,111). The addition of an ROM scavenger, catalase (2, 4, and 8 μg/ml), to the tissue suspension inhibited chemiluminescence produced by both noncancerous (—74%, —85%, and —71%) and cancerous (—11%, —61%, and — 53 %) tissues. This study shows that colonic cancerous tissue contains high levels of ROM, which may play an important role in the pathogenesis of colon cancer.  相似文献   
993.
Osteoporosis is a major growing public health problem and it is clear that much needs to be done to bridge the gap between patients and practitioners. However, the educator must have a valid and reliable tool to evaluate the effectiveness of the teaching and learning that are done. Osteoporosis Knowledge Tool (OKT) provides an important strategy for healthcare professionals to start early intervention for patients who are at risk of osteoporosis. The aims of this study were to translate and examine the psychometric properties of the Malaysian version of the Osteoporosis Knowledge Tool (OKT-M) among 250 type 2 diabetes patients and to assess factors that affect diabetic patients’ osteoporosis knowledge. The OKT English version was translated and validated using the internationally accepted and recommended methodology. The sensitivity and specificity of OKT-M was calculated using receiver operating characteristic curve analysis. The face and content validity showed acceptable results. Internal consistency, test–retest reliability, mean difficulty factor and discriminatory power values were 0.72, 0.83, 0.47 ± 0.16 and 0.96, respectively. The cut-off point of the OKT-M to predict osteoporosis/osteopenia was 14 with optimal sensitivity (84.1 %) and specificity (85.5 %). Regression analysis revealed that health belief, self-efficacy and some demographic data had an impact on the OKT-M. The findings of this validation study indicate that the OKT-M is a reliable and valid tool with good psychometric properties in the Malaysian setting. The OKT-M is an appropriate tool for application in clinical setting to identify patients need for a bone health-promoting intervention regarding lifestyle behaviour changes.  相似文献   
994.
995.
New York City (NYC) jails are the epicenter of an epidemic that overwhelmingly affects Black and Hispanic men and offer a significant opportunity for public health intervention. The NYC Department of Health and Mental Hygiene instituted population based approaches to identify the HIV-infected, initiate discharge planning at jail admission, and facilitate post-release linkages to primary care. Using a caring and supportive ‘warm transitions’ approach, transitional care services are integral to continuity of care. Since 2010, over three-quarters of known HIV-infected inmates admitted to jails received discharge plans; 74 % of those released were linked to primary care. The EnhanceLink initiative’s new Health Liaison, a lynchpin role, facilitated 250 court-led placements in medical alternatives to incarceration. Transitional care coordination programs are critical to facilitate continuity of care for people with chronic health conditions including the HIV-infected returning home from jail and for the public health of the communities to which they return.  相似文献   
996.
Research into HIV and men who have sex with men’s (MSM) health in South Africa has been largely confined to the metropolitan centres. Only two studies were located making reference to MSM in rural contexts or same-sex behaviors among men in the same. There is growing recognition in South Africa that MSM are not only disproportionately affected by HIV and have been underserved by the country’s national response, but that they contribute significantly to sustaining the high number of new infections recorded each year. We argue that to meet the objectives of the country’s national strategic plan for HIV, STI and TB it is important we know how these behaviours may be contributing to the sustained rural HIV epidemic in the youngest age groups and determine what constitutes appropriate and feasible programmatic response that can be implemented in the country’s public sector health services.  相似文献   
997.
Spontaneous coronary artery dissection is a rare but increasingly recognized cause of acute myocardial ischemia in young adults, especially in women. We report a case of spontaneous coronary dissection in a young healthy man who was also a carrier of the factor V Leiden gene mutation.  相似文献   
998.
999.
This article synthesizes diverse official reports, statistics, and scientific papers that present demographic, economic, environmental, and social trends impacting on the health and quality of life of citizens living in European cities. A literature review led to the identification of some key challenges including an aging society, migration flows, inequalities in health, global change, and risk behaviors that should be addressed in order to promote urban health. Other challenges, such as food production and consumption, are also relevant, but not included. Cities that have participated in one or more of the phases of the WHO European Healthy Cities Network have implemented a number of policies, programs, and measures to deal with the challenges discussed in this article. Some contributions are presented to illustrate how health and quality of life in urban areas can be promoted by local authorities.  相似文献   
1000.
Decision analytic models play an increasingly important role in the economic evaluation of health technologies. Given uncertainties around the assumptions used to develop such models, several guidelines have been published to identify and assess ‘best practice’ in the model development process, including general modelling approach (e.g., time horizon), model structure, input data and model performance evaluation. This paper focuses on model performance evaluation. In the absence of a sufficient level of detail around model performance evaluation, concerns regarding the accuracy of model outputs, and hence the credibility of such models, are frequently raised. Following presentation of its components, a review of the application and reporting of model performance evaluation is presented. Taking cardiovascular disease as an illustrative example, the review investigates the use of face validity, internal validity, external validity, and cross model validity. As a part of the performance evaluation process, model calibration is also discussed and its use in applied studies investigated. The review found that the application and reporting of model performance evaluation across 81 studies of treatment for cardiovascular disease was variable. Cross-model validation was reported in 55 % of the reviewed studies, though the level of detail provided varied considerably. We found that very few studies documented other types of validity, and only 6 % of the reviewed articles reported a calibration process. Considering the above findings, we propose a comprehensive model performance evaluation framework (checklist), informed by a review of best-practice guidelines. This framework provides a basis for more accurate and consistent documentation of model performance evaluation. This will improve the peer review process and the comparability of modelling studies. Recognising the fundamental role of decision analytic models in informing public funding decisions, the proposed framework should usefully inform guidelines for preparing submissions to reimbursement bodies.  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