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   35498篇
  免费   2268篇
  国内免费   103篇
耳鼻咽喉   307篇
儿科学   1171篇
妇产科学   1069篇
基础医学   4247篇
口腔科学   490篇
临床医学   6131篇
内科学   5890篇
皮肤病学   382篇
神经病学   3521篇
特种医学   734篇
外国民族医学   1篇
外科学   3630篇
综合类   349篇
现状与发展   1篇
一般理论   50篇
预防医学   4918篇
眼科学   494篇
药学   2149篇
中国医学   34篇
肿瘤学   2301篇
  2023年   208篇
  2022年   343篇
  2021年   651篇
  2020年   452篇
  2019年   694篇
  2018年   866篇
  2017年   606篇
  2016年   687篇
  2015年   731篇
  2014年   1063篇
  2013年   1745篇
  2012年   2463篇
  2011年   2628篇
  2010年   1379篇
  2009年   1207篇
  2008年   2353篇
  2007年   2567篇
  2006年   2446篇
  2005年   2345篇
  2004年   2210篇
  2003年   2080篇
  2002年   1995篇
  2001年   363篇
  2000年   330篇
  1999年   403篇
  1998年   414篇
  1997年   349篇
  1996年   301篇
  1995年   314篇
  1994年   250篇
  1993年   251篇
  1992年   219篇
  1991年   221篇
  1990年   219篇
  1989年   187篇
  1988年   164篇
  1987年   159篇
  1986年   143篇
  1985年   156篇
  1984年   163篇
  1983年   164篇
  1982年   171篇
  1981年   155篇
  1980年   142篇
  1979年   97篇
  1978年   110篇
  1977年   83篇
  1976年   71篇
  1975年   59篇
  1974年   66篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
We identified 18 patients with double-orifice mitral valve (DOMV) and intact atrioventricular (AV) septum out of 40,179 echocardiographic studies performed between 1997 and 2002 at Children's Hospital, Denver, CO. In this study we describe (1) the anatomic characteristics of the DOMV in the absence of AV septal defect, (2) the function of the mitral valve by spectral and color Doppler flow mapping, and (3) associated lesions. The topographic location of the orifices in the leaflets suggests possible embryologic mechanisms of DOMV. In this series, DOMV was most commonly associated with left-sided obstructive lesions (in 39% of patients). Spectral and color Doppler interrogation demonstrated a normal flow profile in most cases; only 2 patients had significant mitral regurgitation or stenosis. Therefore, due to the uncertain natural history of this lesion and the potential need for endocarditis prophylaxis, careful imaging of the mitral valve is recommended, particularly in the presence of left-sided obstructive lesions.  相似文献   
74.
75.
Poverty influences health status, life expectancy, health behaviours, and use of health services. This study examined factors influencing the use of health-related services by people living in poverty. In the first phase, 199 impoverished users of health-related services in 2 large Canadian cities were interviewed by their peers. In the second phase, group interviews with people living in poverty (n = 52) were conducted. Data were analyzed using thematic content analysis. Diverse health-related services were used to meet basic and health needs, to maintain human contact, and to cope with life's challenges. Use of services depended on proximity, affordability, convenience, information, and providers' attitudes and behaviours. Use was impeded by inequities based on income status. To promote the health of people living in poverty, nurses and other health professionals can enhance the accessibility and quality of services, improve their interactions with people living in poverty, provide information about available programs, offer coordinated community-based services, collaborate with other sectors, and advocate for more equitable services and policies.  相似文献   
76.
77.
An ex post facto correlational study was conducted to examine predictors of quality of life in persons 3 to 6 months after a myocardial infarction. Self-care resources, self-care knowledge (needs), activity level, and selected demographic variables were examined as predictor variables. A convenience sample of 86 subjects with a mean age of 61 years, was recruited for participation in this study. The study that explained 35% of the variance in quality of life included self-care resources available, activity level, and self-care needs. Modeling and Role Modeling Paradigm provided a useful explanation of how self-care resources and self-care knowledge can be applied to persons recovering from myocardial infarction.  相似文献   
78.
A patient-centered paradigm for clinical research and medical care is presented as a solution to the problem of declining innovation and increasing costs and development time in the pipeline for new therapies. Fundamental differences in values and motivations among scientists, clinicians, industry sponsor, and patients in neurotherapeutics provide a framework for analysis of ethical conflicts and the loss of public confidence in medical research. Parkinson advocates’ views on clinical trial participation, perceived risks and benefits, placebo controls, and sham surgery are presented. These views reflect the sense of urgency and the unique perspective that comes from living with this progressive, debilitating condition full time. A patient-centered paradigm that includes authentic voices of patients as collaborators at every stage of development will help to resolve conflicts, build trust, recruit trial participants, and accelerate new therapies. Key elements are adaptive clinical trial methods and the development of information technology for the assessment of outcomes and surveillance of safety over the life cycle of a medical product. Supported by the Parkinson’s Disease Foundation, the Parkinson Pipeline Project is a grassroots group of Parkinson’s patients whose goal is to represent an authentic voice for patients in the treatment development process. This group promotes education and communication between members of the Parkinson’s community and active stakeholders in medical research, industry, and regulatory agencies. Its members are an example of a new breed of knowledgeable consumers, armed with first-hand access to research findings and reinforced by on-line connections to like-minded peers throughout the world.  相似文献   
79.
Society is currently on the threshold of a new revolution in understanding the interaction of genes and the environment. This research has profound implications for understanding occupational disease and will present ethical challenges to occupational health practice. The public must be educated about the potential promise, as well as the threats, posed by emerging genetic technologies.  相似文献   
80.
PURPOSE: The aim of the study was to delineate differences in saccadic adaptation characteristics between a population of racquet sports athletes and nonathletes. METHODS: Eye movements were recorded at 120 Hz using a video-based eye tracker (ELMAR 2020) in a sample of 27 athletes (varsity badminton and squash players) and 14 nonathletes (<3 hours/week participation in recreational sports). Responses to negative positional error and positive positional error were studied in two sessions on separate days. Negative positional errors were induced by displacing the stimuli backwards by 3 degrees from the initial target step (12 degrees). Likewise, positive positional errors were induced by displacing the stimuli forward by 3 degrees . Amplitude gains were calculated for trials before, during, and after the adaptation phase. The magnitude and the rate of change of saccadic adaptation were determined from the amplitude gains. Differences between the groups were compared using regression analysis. RESULTS: No significant differences were found between the two groups in the magnitude of saccadic adaptation, both for negative (athletes -60%, nonathletes -57%) and positive (athletes +26%, and nonathletes +27%) positional error. Racquet sports athletes showed a significantly faster rate of adaptation for the positive positional error. A significant difference was not observed in the rate of adaptation for the negative positional error. CONCLUSIONS: Racquet sports athletes and nonathletes adapt to positional error signals by similar amounts. However, racquet sports athletes respond to positive positional errors at a faster rate, suggesting that a strategic component or environmental influences (such as practice) may play a role in saccadic adaptation.  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