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   13573篇
  免费   917篇
  国内免费   37篇
耳鼻咽喉   99篇
儿科学   433篇
妇产科学   290篇
基础医学   1588篇
口腔科学   210篇
临床医学   1202篇
内科学   3182篇
皮肤病学   210篇
神经病学   1306篇
特种医学   479篇
外科学   1663篇
综合类   249篇
一般理论   6篇
预防医学   1548篇
眼科学   251篇
药学   976篇
中国医学   56篇
肿瘤学   779篇
  2023年   74篇
  2022年   78篇
  2021年   270篇
  2020年   148篇
  2019年   268篇
  2018年   433篇
  2017年   310篇
  2016年   276篇
  2015年   317篇
  2014年   391篇
  2013年   575篇
  2012年   854篇
  2011年   965篇
  2010年   560篇
  2009年   447篇
  2008年   831篇
  2007年   924篇
  2006年   852篇
  2005年   880篇
  2004年   847篇
  2003年   833篇
  2002年   780篇
  2001年   323篇
  2000年   399篇
  1999年   282篇
  1998年   115篇
  1997年   65篇
  1996年   62篇
  1995年   63篇
  1994年   71篇
  1993年   51篇
  1992年   136篇
  1991年   106篇
  1990年   85篇
  1989年   88篇
  1988年   75篇
  1987年   75篇
  1986年   63篇
  1985年   61篇
  1984年   35篇
  1983年   38篇
  1982年   26篇
  1981年   32篇
  1979年   38篇
  1978年   40篇
  1977年   31篇
  1976年   31篇
  1975年   22篇
  1973年   24篇
  1972年   25篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
OBJECTIVE: To characterize sports and recreation related (SR) injury episodes in the US population. SR activities are growing in popularity suggesting the need for increased awareness of SR injuries as a public health concern for physically active persons of all ages in the US population. SETTING: The National Health Interview Survey (NHIS) is a face-to-face household survey conducted yearly by the National Center for Health Statistics, part of the Centers for Disease Control and Prevention. Demographic and health data are collected from a nationally representative sample of the civilian, non-institutionalized population residing in the US. METHODS: Medically attended injury events reported in the 1997-99 Injury Section of the NHIS were categorized according to the associated sport or recreational activity using a classification scheme based on the International Classification of External Causes of Injury system. Episodes where the injured person received any type of medical attention (that is, medical advice or treatment) from any health care provider were used to report the incidence, severity, and nature of SR injuries sustained by US citizens. RESULTS: Annually, an estimated seven million Americans received medical attention for SR injuries (25.9 injury episodes per 1000 population). For 5-24 year olds, this national estimate was about 42% higher than estimates based on SR injuries seen only in emergency departments over a similar time frame. The highest average annual SR injury episode rates were for children ages 5-14 years (59.3 per 1000 persons) and persons aged 15-24 years (56.4 per 1000 persons). The SR injury episode rate for males was more than twice the rate for females. The age adjusted injury rate for whites was 1.5 times higher than for blacks (28.8 v 19.0 per 1000 population). Basketball was the most frequently mentioned SR activity when the injury episode occurred, with a rate of about four injury events per 1000 population. Strains and sprains accounted for 31% of injury episodes. An estimated 1.1 million SR episode related injuries involve the head or neck region, of which 17% were internal head injuries. The most common mechanisms of injury were struck by/against (34%), fall (28%), and overexertion (13%). CONCLUSION: As physical activity continues to be promoted as part of a healthy lifestyle, SR injuries are becoming an important public health concern for both children and adults. Prevention efforts aimed at reducing SR injuries through targeting high risk activities, places of occurrence, activity, risk behaviors, and use of protective devices need to go beyond focusing on children and also consider physically active adults.  相似文献   
93.
94.
Colorectal cancer is a complex disease from a genetic point of view because both genetic and environmental factors interact in its development. Only familial adenomatous polyposis (FAP) follows mendelian genetics, in that mutations of the APC gene lead to development of the tumours. Lynch syndrome is the most frequent form of hereditary colorectal cancer and appears to be associated with other types of extracolonic cancers. The genetic basis has been established as a defect in DNA mismatch repair genes, and there is genetic heterogeneity due to the involvement of several genes in this system. Germinal mutations in these genes predispose to appearance of the syndrome. The aim of this study is to describe the tumoral spectrum of 10 families, comprising a total of 488 individuals, from the island of Tenerife (Canary Islands) and to assess whether the geographical isolation of this population has changed any features of the tumoral spectrum of the syndrome in comparison with studies that cover larger geographical areas with more genetic exchange. From our results we can conclude that the genetic drift and consanguinity in this population with a demographic history of isolation did not significantly alter the tumoral spectrum of the syndrome. Our data confirm that families affected by Lynch syndrome are a high-risk population and should be closely monitored, since their careful supervision has been shown to be useful in preventing cancer. We also emphasize the importance of developing a complete family history that permits these families to be identified together with a mutational screening of DNA mismatch repair genes (mainly MLH1 and MSH2 genes) with the aim of a possible identification of members of a family that should be carefully monitored (the carriers of germline mutations in these genes), whereas the remaining members, originally, are no more at risk than the general population.  相似文献   
95.
Improving the quality of care for patients with chronic illness has become a high priority. Implementing training programs in disease management (DM) so the next generation of physicians can manage chronic illness more effectively is challenging. Residency training programs have no specific mandate to implement DM training. Additional barriers at the training facility include: 1) lack of a population-based perspective for service delivery; 2) weak support for self-management of illness; 3) incomplete implementation due to physician resistance or inertia; and 4) few incentives to change practices and behaviors. In order to overcome these barriers, training programs must take the initiative to implement DM training that addresses each of these issues. We report the implementation of a chronic illness management curriculum based on the Improving Chronic Illness Care (ICIC) Model. Features of this process included both patient care and learner objectives. These were: development of a multidisciplinary diabetes DM team; development of a patient registry; development of diabetes teaching clinics in the family practice center (nutrition, general management classes, and one-on-one teaching); development of a group visit model; and training the residents in the elements of the ICIC Model, ie, the community, the health system, self-management support, delivery system design, decision support, and clinical information systems. Barriers to implementing these curricular changes were: the development of a patient registry; buy-in from faculty, residents, clinic leadership, staff, and patients for the chronic care model; the ability to bill for services and maintain clinical productivity; and support from the health system key stakeholders for sustainability. Unique features of each training site will dictate differences in emphasis and structure; however, the core principles of the ICIC Model in enhancing self-management may be generalized to all sites.  相似文献   
96.
OBJECTIVE: To report an influenza B infection with associated myocarditis and severe skeletal myositis. DESIGN: Case report. SETTING: Cardiac intensive care unit in a university-affiliated children's hospital. PATIENT: A 4-yr-old girl. RESULTS: The patient was successfully supported with extracorporeal membrane oxygenation for profound myocardial dysfunction and a combination of plasmapheresis and continuous venovenous hemodialysis for rhabdomyolysis and acute renal failure. CONCLUSIONS: This case provides a reminder that patients presenting with viral illness or myoglobinuria accompanied by renal failure, with or without associated myocarditis, may be demonstrating symptoms of influenza B.  相似文献   
97.
AIMS: To determine whether the monitoring of respiratory disease progression in children with cystic fibrosis (CF) can be made using six pre-selected computed tomography (CT) cuts in lieu of the conventional full study. METHODS: Forty one lung CT scans from 21 paediatric patients with CF were analysed. The Bhalla and Nathanson scores of the total lung CT and the six pre-selected CT cuts were compared. RESULTS: The Bhalla mean score of the total lung CT evaluated by two radiologists was 5.62. It was 5.36 when just the six pre-selected sections were evaluated. The difference between means was not statistically significant. The Nathanson mean score of the total lung CT evaluated by both radiologists was 66.11; it was 66.51 when just the six pre-selected sections were evaluated. The difference between means was not statistically significant. The mean total radiation dose from a single whole lung CT scan was 716.22 mGy.cm. A dose of 250.66 mGy.cm was estimated if only six sections were used, with a reduction in radiation of about 65%. CONCLUSION: It is possible to obtain the same radiological information from six pre-selected CT cuts as it is from a full pulmonary CT scan, thereby markedly reducing radiation exposure for children who will require repeat investigations in the future.  相似文献   
98.
OBJECTIVE: Community-based lifestyle intervention may offer the best means of reducing the global epidemic of childhood obesity and its consequences, yet few successful interventions have been reported. The objective was to determine whether increasing extra-curricular levels of activity could reduce weight gain in children. METHODS: A controlled intervention study was conducted using standardised methods to assess outcomes. Two comparable relatively rural communities in Otago, New Zealand formed intervention and control settings. Height, weight, waist circumference and participation in physical activity (by accelerometry) were measured at baseline and at 1 year in 384 children aged 5 to 12 years representing the majority of children in this age group in intervention and control communities. Community Activity Co-ordinators were employed at each school in the intervention area. Their brief was to widen exposure to activity and engage children not interested in traditional sporting activities by encouraging lifestyle-based activities (e.g. walking) and non-traditional sports (e.g. golf and taekwondo) during extra-curricular time at school, after school and during vacations. Simple dietary advice was offered and the wider community was encouraged to participate. RESULTS: Average accelerometry counts at 1 year were 28% (95% CI: 11 to 47%) higher in intervention compared with control children after adjusting for age, sex, baseline values and school. Intervention children spent less time in sedentary activity (ratio 0.91, p = 0.007) and more time in moderate (1.07, p = 0.001) and moderate/vigorous (1.10, p = 0.01) activity. Adjusted mean BMI Z-score was lower in intervention relative to control children by -0.12 units (95% CI: -0.22 to -0.02). CONCLUSION:. An intervention designed to maximise opportunities for physical activity during extra-curricular time at school and during leisure time through the provision of community-based Activity Co-ordinators significantly increased participation in physical activity and slowed unhealthy weight gain in primary school-aged children.  相似文献   
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