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   97476篇
  免费   6867篇
  国内免费   510篇
耳鼻咽喉   1210篇
儿科学   2298篇
妇产科学   1408篇
基础医学   12518篇
口腔科学   2367篇
临床医学   9665篇
内科学   21459篇
皮肤病学   1522篇
神经病学   9367篇
特种医学   3980篇
外国民族医学   1篇
外科学   16151篇
综合类   822篇
一般理论   194篇
预防医学   6628篇
眼科学   1850篇
药学   5892篇
中国医学   139篇
肿瘤学   7382篇
  2023年   867篇
  2022年   1499篇
  2021年   3297篇
  2020年   1826篇
  2019年   2837篇
  2018年   3324篇
  2017年   2359篇
  2016年   2552篇
  2015年   2870篇
  2014年   3955篇
  2013年   5088篇
  2012年   7661篇
  2011年   7772篇
  2010年   4294篇
  2009年   3723篇
  2008年   6399篇
  2007年   6165篇
  2006年   5973篇
  2005年   5887篇
  2004年   5318篇
  2003年   4875篇
  2002年   4385篇
  2001年   649篇
  2000年   514篇
  1999年   715篇
  1998年   898篇
  1997年   715篇
  1996年   583篇
  1995年   572篇
  1994年   461篇
  1993年   463篇
  1992年   390篇
  1991年   351篇
  1990年   311篇
  1989年   309篇
  1988年   310篇
  1987年   286篇
  1986年   297篇
  1985年   305篇
  1984年   366篇
  1983年   324篇
  1982年   348篇
  1981年   344篇
  1980年   273篇
  1979年   167篇
  1978年   202篇
  1977年   182篇
  1976年   132篇
  1975年   143篇
  1974年   139篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
51.
52.
53.
PURPOSE: To compare, using a prospective, randomized controlled study, three methods of teaching a medical school parasitology course: computer-based instruction, traditional lecture-based instruction, and a combination of computer-based and lecture-based instruction. METHOD: A single class of the University of Utah School of Medicine was randomized into three study groups for the second-year parasitology course. The computer group (n = 29) used a locally developed interactive parasitology computer program; the lecture group (n = 32) had traditional lectures, and the combined group (n = 33) used both the computer program and lectures. Students' knowledge was assessed using a pretest, a final examination, and a posttest administered four months after the course. Students also used logs to track the amounts of time they spent studying. Their impressions and course evaluations were collected using a standardized course-evaluation form. RESULTS: The groups' scores on the pretest, final examination, and posttest were not statistically significantly different. Students in the computer group averaged 26.8 hours of studying over the two-week course compared with 32.1 hours in the lecture group and 32.7 hours in the combined group. The difference in study times between the computer and combined groups yielded a significant p value of 0.036. Students were generally positive about the course and the computer program. CONCLUSION: Students can learn parasitology from computer-based instruction as effectively as from traditional lecture-based instruction, and they can do so in less time.  相似文献   
54.
Three evaluation instruments (global, check-list, and criterion referenced) were used by experienced and inexperienced examiners to evaluate dental sealant end products on 40 extracted teeth. Intra- and interexaminer reliabilities were measured. Experienced examiners achieved higher intrarater reliabilities with all three evaluation instruments than did inexperienced examiners. The highest intraexaminer agreement for all examiners occurred with use of the global evaluation. The highest interexaminer reliability was achieved with the second use of the criterion-referenced evaluation by the experienced examiner. Interexaminer reliability was improved for both types of examiners with the criterion-referenced evaluation.  相似文献   
55.
<西太平洋地区本科医学教育指导原则>为医学院校提供了基准和质量改进的努力方向,并将有助于实现可持续的课程改革.本次会议将是中国在改善本科医学教育质量上迈出的重要一步.世界卫生组织愿与中国政府合作并提供支持.  相似文献   
56.
57.
Writer's cramp is a task-specific dystonia that leads to involuntary hand postures during writing. Abnormalities of sensory processing may play a pathophysiological role in this disorder. Electrophysiology studies in a monkey model of focal dystonia have revealed de-differentiation of sensory maps and the existence of single cells in hand regions of area 3b with enlarged receptive fields that extend to the surfaces of more than one digit. These changes may lead to abnormal processing of simultaneous sensory inputs. To study abnormal processing of simultaneous sensory information in adult humans with writer's cramp, we used functional magnetic resonance imaging to compare the response in primary sensory cortex with simultaneous tactile stimulation of the index and middle finger, with the response to stimulation of each finger alone. We tested five patients with writer's cramp and seven unaffected (normal) subjects. In the normal subjects, a linear combination of the activation patterns for individual finger stimulation predicts the pattern of activity for combined stimulation with 12% error. In writer's cramp patients, the linear combination predicted the combined stimulation pattern with 30% error. Results indicate a nonlinear interaction between the sensory cortical response to individual finger stimulation in writer's cramp. This altered interaction may contribute to the motor abnormalities.  相似文献   
58.
59.
60.
Background  Stress gated myocardial perfusion single photon emission computed tomography (gSPECT) is increasingly used before and after intercurrent therapeutic intervention and is the basis for ongoing evaluation in the Department of Veterans Affairs clinical outcomes utilizing revascularization and aggressive drug evaluation (COURAGE) trial. Methods and Results  The COURAGE trial is a North American multicenter randomized clinical trial that enrolled 2287 patients to aggressive medical therapy vs percutaneous coronary intervention plus aggressive medical therapy. Three COURAGE nuclear substudies have been designed. The goals of substudy 0 are to examine the diagnostic accuracy of the extent and severity of inducible ischemia at baseline in COURAGE patients compared with patient symptoms and quantitative coronary angiography and to explore the relationship between inducible ischemia and the benefit from revascularization when added to medical therapy. Substudy 1 will correlate the extent and severity of provocative ischemia with the frequency, quality, and instability of recurrent symptoms in postcatheterization patients. Substudy 2 (n _ 300) will examine the usefulness of sequential gSPECT monitoring 6 to 18 months after therapeutic intervention. Together, these nuclear substudies will evaluate the role of gSPECT to determine the effectiveness of aggressive risk-factor modifications, lifestyle interventions, and anti-ischemic medical therapies with or without revascularization in reducing patients’ ischemic burdens. Conclusions  The unfolding of evidence on the application of gSPECT in trials such as COURAGE defines a new era for nuclear cardiology. We hope the evidence that emerges from the COURAGE trial will further establish the role of nuclear imaging in the evidence-based management of patients with stable coronary disease. The COURAGE trial was supported by the Cooperative Studies Program of the Department of Veterans Affairs Office of Research and Development in collaboration with the Canadian Institutes of Health Research. Unrestricted research grants were obtained from Merck & Co; Pfizer Pharmaceuticals; Bristol-Myers Squibb Medical Imaging; Astellas Pharma; Kos Pharmaceuticals; Data Scope; Astra Zeneca Pharmaceuticals; Astra-Zeneca-Canada; Schering-Plough Coorporation, Ltd; Sanofi-Aventis, Inc; First Horizon; and GE Healthcare. All industrial funding for this trial was directed through the Department of Veterans Affairs. Additional funding for this substudy was provided by grants to the Department of Veterans Affairs and Canadian Institutes of Health Research from Astellas Pharma and Bristol-Myers-Squibb Medical Imaging.  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