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   2429篇
  免费   204篇
  国内免费   7篇
耳鼻咽喉   38篇
儿科学   123篇
妇产科学   57篇
基础医学   243篇
口腔科学   66篇
临床医学   394篇
内科学   388篇
皮肤病学   89篇
神经病学   174篇
特种医学   164篇
外科学   303篇
综合类   52篇
一般理论   5篇
预防医学   222篇
眼科学   62篇
药学   152篇
肿瘤学   108篇
  2021年   43篇
  2020年   21篇
  2019年   40篇
  2018年   41篇
  2017年   40篇
  2016年   42篇
  2015年   47篇
  2014年   75篇
  2013年   89篇
  2012年   65篇
  2011年   96篇
  2010年   79篇
  2009年   65篇
  2008年   100篇
  2007年   101篇
  2006年   84篇
  2005年   101篇
  2004年   95篇
  2003年   72篇
  2002年   60篇
  2001年   69篇
  2000年   69篇
  1999年   48篇
  1998年   42篇
  1997年   46篇
  1996年   47篇
  1995年   32篇
  1994年   27篇
  1993年   26篇
  1992年   36篇
  1991年   30篇
  1990年   44篇
  1989年   46篇
  1988年   48篇
  1987年   44篇
  1986年   44篇
  1985年   44篇
  1984年   42篇
  1983年   30篇
  1982年   31篇
  1981年   27篇
  1979年   31篇
  1978年   20篇
  1977年   22篇
  1975年   25篇
  1973年   21篇
  1971年   26篇
  1970年   22篇
  1968年   19篇
  1967年   17篇
排序方式: 共有2640条查询结果,搜索用时 561 毫秒
1.
2.
3.
Richard E. Clark in his widely published comprehensive studies and meta-analyses of the literature on computer assisted instruction (CAI) has decried the lack of carefully controlled research, challenging almost every study which shows the computer-based intervention to result in significant post-test proficiency gains over a non-computer-based intervention. We report on a randomized study in a medical school setting where the usual confounders found by Clark to plague most research, were carefully controlled. PlanAlyzer is a microcomputer-based, self-paced, case-based, event-driven system for medical education which was developed and used in carefully controlled trials in a second year medical school curriculum to test the hypothesis that students with access to the interactive programs could integrate their didactic knowledge more effectively and/or efficiently than with access only to traditional textual “nonintelligent” materials. PlanAlyzer presents cases, elicits and critiques a student's approach to the diagnosis of two common medical disorders: anemias and chest pain. PlanAlyzer uses text, hypertext, images and critiquing theory. Students were randomized, one half becoming the experimental group who received the interactive PlanAlyzer cases in anemia, the other half becoming the controls who received the exact same content material in a text format. Later in each year there was a crossover, the controls becoming the experimentals for a similar intervention with the cardiology PlanAlyzer cases. Preliminary results at the end of the first two full trials shows that the programs have achieved most of the proposed instructional objectives, plus some significant efficiency and economy gains. 96 faculty hours of classroom time were saved by using PlanAlyzer in their place, while maintaining high student achievement. In terms of student proficiency and efficiency, the 328 students in the trials over two years were able to accomplish the project's instructional objectives, and the experimentals accomplished this in 43% less time than the controls, achieving the same level of mastery. However, in spite of these significant efficiency findings, there have been no significant proficiency differences (as measured by current factual and higher order multiple choice post-tests) between the experimental and control groups. Very careful controls were used to avoid what Clark has found to be the most common confounders of CAI research. Accordingly, this research proved Clark's rival hypothesis, that the computer, in itself, does not appear to contribute to proficiency gains, at least as measured by our limited post-testing. Clark's position is that the computer is primarily a vehicle—as is either a pill or a hypodermic needle for delivering a drug. The hypodermic needle can deliver the drug more efficiently than can the pill, (as can the computer deliver the subject matter content more efficiently, as our research indicates), but the same content is delivered. At the same time, we proved our own hypothesis, as far as efficiency gains resulting from the computer are concerned. However, going beyond Clark's research, we may be teaching processes both more effectively and efficiently with the computer (experience in problem-solving or clinical reasoning and pattern recognition) which our current post-tests do not adequately measure. Our on-going research suggests additional inquiry in several areas: better evaluation instruments to measure the clinical reasoning skills PlanAlyzer was designed to teach; the addition of more advanced cases to determine if this might transform efficiency gains of the computer group into proficiency gains; the addition of enhanced graphic decision support tools and other pedagogical enhancements including cognitive feedback to strengthen PlanAlyzer's power to teach complex concepts of medical decision-making.  相似文献   
4.

Background  

Pulmonary dysfunction following cardiac surgery is believed to be caused, at least in part, by a lung vascular injury and/or atelectasis following cardiopulmonary bypass (CPB) perfusion and collapse of non-ventilated lungs.  相似文献   
5.

Background  

Shoulder disorders are a common health problem in western societies. Several treatment protocols have been developed for the clinical management of persons with shoulder pain. However available evidence does not support any protocol as being superior over others. Systematic reviews provide some evidence that certain physical therapy interventions (i.e. supervised exercises and mobilisation) are effective in particular shoulder disorders (i.e. rotator cuff disorders, mixed shoulder disorders and adhesive capsulitis), but there is an ongoing need for high quality trials of physical therapy interventions. Usually, physical therapy consists of active exercises intended to strengthen the shoulder muscles as stabilizers of the glenohumeral joint or perform mobilisations to improve restricted mobility of the glenohumeral or adjacent joints (shoulder girdle). It is generally accepted that a-traumatic shoulder problems are the result of impingement of the subacromial structures, such as the bursa or rotator cuff tendons. Myofascial trigger points (MTrPs) in shoulder muscles may also lead to a complex of symptoms that are often seen in patients diagnosed with subacromial impingement or rotator cuff tendinopathy. Little is known about the treatment of MTrPs in patients with shoulder disorders.  相似文献   
6.
7.
8.
BACKGROUND AND AIM: Peptic ulcer disease is believed to be less common and less severe as a result of modern medical treatment. We therefore examined changes in the admission rates for patients with duodenal ulcer and gastric ulcer, both emergency (for haemorrhage, perforation or severe pain) and for elective surgery, before and since the introduction of the new advances in therapy. These admission indices reflect disease prevalence and severity. PATIENTS AND METHODS: We identified admission rates during 1972--2000 within the Trent Regional Health Authority, UK (population 4.7 million), from computerised patient information using diagnostic search codes ICD8-10 and expressed as rates per million resident population. Drug expenditure details were obtained from the Department of Health. RESULTS: Emergency admission rates as a whole changed little, a decline in the young being offset by an increase in the elderly. Haemorrhage was the most common reason (approximately 115 per million for duodenal ulcer and 87 for gastric ulcer) throughout [compared with perforation (80 and 21) and pain (90 and 68)]. In contrast, elective surgery has almost disappeared; this reduction began before the introduction of modern treatment. CONCLUSION: Emergency admission rates for duodenal and gastric ulcer for complications or severe pain have fluctuated over the last three decades but with little overall change. In contrast, elective surgery has declined dramatically, as a result of advances in treatment but also from changes in the natural history.  相似文献   
9.
10.
This study was conducted to determine whether general case simulation instruction on selected job task sequences and teaching examples, which sampled the range of stimulus/response variation encountered in two community jobs, resulted in the generalized performance of specific community job requirements by four young adults with severe handicaps. A multiple baseline across subjects and behaviors design was used to assess subject performance in simulation instruction, on concurrent and subsequent actual job probes, and in actual job instruction. Data indicated that simulation instruction on two representative teaching examples for each of two job task sequences resulted in concurrent generalized performance on six response examples for each task sequence, and in subsequent improvements in job entry skills which were maintained and extended during actual job instruction and instructor withdrawal phases. Results are discussed in terms of potential uses and misuses of general case simulations of community job skills.  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