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   2925篇
  免费   185篇
  国内免费   7篇
耳鼻咽喉   56篇
儿科学   86篇
妇产科学   108篇
基础医学   530篇
口腔科学   58篇
临床医学   230篇
内科学   510篇
皮肤病学   93篇
神经病学   311篇
特种医学   43篇
外国民族医学   2篇
外科学   319篇
综合类   18篇
预防医学   263篇
眼科学   30篇
药学   224篇
中国医学   1篇
肿瘤学   235篇
  2023年   25篇
  2022年   26篇
  2021年   82篇
  2020年   57篇
  2019年   83篇
  2018年   82篇
  2017年   58篇
  2016年   68篇
  2015年   80篇
  2014年   119篇
  2013年   125篇
  2012年   210篇
  2011年   189篇
  2010年   112篇
  2009年   98篇
  2008年   153篇
  2007年   169篇
  2006年   144篇
  2005年   147篇
  2004年   146篇
  2003年   128篇
  2002年   122篇
  2001年   54篇
  2000年   33篇
  1999年   42篇
  1998年   23篇
  1997年   16篇
  1996年   13篇
  1995年   12篇
  1994年   15篇
  1993年   10篇
  1992年   29篇
  1991年   23篇
  1990年   25篇
  1989年   22篇
  1988年   30篇
  1987年   29篇
  1986年   24篇
  1985年   20篇
  1984年   14篇
  1983年   17篇
  1979年   12篇
  1978年   10篇
  1974年   10篇
  1971年   8篇
  1970年   11篇
  1967年   8篇
  1876年   8篇
  1872年   9篇
  1868年   8篇
排序方式: 共有3117条查询结果,搜索用时 484 毫秒
51.
The aim of this study is to evaluate the clinical and radiological parameters of standard SLA surface implants compared to chemically modified hydrophilic SLActive implants in irradiated patients after the initial 12‐month loading period up to 5 years. Twenty patients with a mean age of 61·1 years were treated with dental implants after ablative surgery and radio‐chemotherapy of oral cancer. All patients were non‐smokers. The placement of 102 implants (50 SLA, 52 SLActive) was performed bilaterally according to a split‐mouth design. Mean crestal bone changes were evaluated using standardised orthopantomographies and clinical parameters. Data were analysed using a Kaplan–Meier curve, Mann–Whitney U‐test and two‐factorial non‐parametric analysis. The average observation period was 60 months. The amount of bone loss at the implant shoulder of SLA implants was mesial and distal 0·7 mm. The SLActive implants displayed a bone loss of mesial 0·6 mm as well as distal 0·7 mm after 5 years. Two SLA implants were lost before loading. One patient lost five implants due to recurrence of a tumour. The overall cumulative 12‐month, 3‐year and 5‐year survival rate of SLA implants was 92%, 80% and 75·8% and of SLActive implants 94·2%, 78·8% and 74·4%, respectively. Eighteen implants were considered lost because the patients had died. Sandblasted acid‐etched implants with or without a chemically modified surface can be used in irradiated patients with a high predictability of success. Lower implant survival rates in patients with irradiated oral cancer may be associated with systemic effects rather than peri‐implantitis.  相似文献   
52.
53.
54.
BackgroundYouth of color from low-income urban communities are crucial participants in research, as their involvement can shape effective, culturally responsive interventions and policy to promote youth health and well-being. These young people, however, are an often-neglected research population, due in part to perceived challenges associated with their inclusion as well as marginalized communities’ justifiable mistrust of research.ObjectivesBased on our experience conducting a school-based randomized intervention trial in Baltimore, Maryland, we present strategies for conducting research with low-income, urban youth of color. We discuss strategies in three domains: university-community partnership development, participant recruitment, and participant retention.MethodsWe reviewed partnership building and recruitment strategies employed by our team across four years of trial implementation and evaluated success of participant retention at our final survey timepoint.ResultsPartnership building was facilitated by selection of a study design that maximized benefits for all participants, promotion of capacity building at partner institutions, and attention to research staff hiring and training practices. Effective study recruitment strategies included personal contact with parents and close cooperation between school personnel and study staff. Providing incentives and collecting multiple types of participant contact information contributed to increased retention rates. On average, those who participated in the final survey timepoint were less likely to be male and Latinx and exhibited more favorable baseline mental health than those who did not, suggesting differential attrition based on youth characteristics.ConclusionsLessons learned from this school-based trial can be applied more broadly to research with low-income urban youth of color. Researchers should strive to maximize scientific rigor, minimize harm to vulnerable adolescents and their communities, promote positive research experiences for young people, and provide concrete benefits to those who participate.  相似文献   
55.
56.
57.
58.
Drug-induced atrial fibrillation   总被引:1,自引:0,他引:1  
Atrial fibrillation (AF) is the most common sustained rhythm disorder observed in clinical practice and predominantly associated with cardiovascular disorders such as coronary heart disease and hypertension. However, several classes of drugs may induce AF in patients without apparent heart disease or may precipitate the onset of AF in patients with preexisting heart disease. We reviewed the literature on drug-induced AF, using the PubMed/Medline and Micromedex databases and lateral references. Successively, we discuss the potential role in the onset of AF of cardiovascular drugs, respiratory system drugs, cytostatics, central nervous system drugs, genitourinary system drugs, and some miscellaneous agents. Drug-induced AF may play a role in only a minority of the patients presenting with AF. Nevertheless, it is important to recognize drugs or other agents as a potential cause, especially in the elderly, because increasing age is associated with multiple drug use and a high incidence of AF. This may contribute to timely diagnosis and management of drug-induced AF.  相似文献   
59.
Since most hip fractures are related to osteoporosis, treating accelerated bone loss can be an important strategy to prevent hip fractures. Thiazides have been associated with reduced age-related bone loss by decreasing urinary calcium excretion.  相似文献   
60.
OBJECTIVES: To determine the prognostic role of orthostatic hypotension for cardiovascular disease (CVD) and all‐cause mortality in elderly people. DESIGN: Prospective study. SETTING: Community based. PARTICIPANTS: Five thousand sixty‐four subjects from the Rotterdam study aged 55 and older. MEASUREMENTS: Orthostatic hypotension was measured using a Dinamap automatic blood pressure recorder. Orthostatic hypotension is defined as a decline in systolic blood pressure of 20 mmHg or more or a decline in diastolic blood pressure of 10 mmHg or more from supine to standing position at any of three measurements taken 1, 2, and 3 minutes after standing. RESULTS: At baseline, 901 subjects had orthostatic hypotension. During follow‐up, 668 subjects had coronary heart disease (CHD) (mean follow‐up 6.0 ± 3.5 years), and 1,835 subjects died (mean follow‐up period 7.8 ± 3.8 years). Orthostatic hypotension increased the risk of CHD (hazard ratio (HR)=1.31, 95% confidence interval (CI)=1.08–1.57) and all‐cause mortality (HR=1.22, 95% CI=1.09–1.36), in models adjusted for age and sex. The risk was slightly lower after additional adjustment for cardiovascular risk factors. In analyses stratified for age, the HRs for all‐cause mortality were 1.80 (95% CI 1.25–2.60), 1.13 (0.89–1.42), and 1.27 (95% CI=1.11–1.44), in the first, second, and third tertile of age, respectively. CONCLUSION: Orthostatic hypotension increases the risk of CHD and all‐cause mortality in elderly people. The risk of CVD and mortality is strongest in younger and very old subjects.  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