全文获取类型
收费全文 | 7133篇 |
免费 | 768篇 |
国内免费 | 170篇 |
专业分类
耳鼻咽喉 | 85篇 |
儿科学 | 318篇 |
妇产科学 | 178篇 |
基础医学 | 303篇 |
口腔科学 | 133篇 |
临床医学 | 1529篇 |
内科学 | 1458篇 |
皮肤病学 | 181篇 |
神经病学 | 460篇 |
特种医学 | 246篇 |
外科学 | 1817篇 |
综合类 | 41篇 |
一般理论 | 5篇 |
预防医学 | 487篇 |
眼科学 | 378篇 |
药学 | 172篇 |
肿瘤学 | 280篇 |
出版年
2023年 | 112篇 |
2021年 | 89篇 |
2020年 | 108篇 |
2019年 | 75篇 |
2018年 | 151篇 |
2017年 | 194篇 |
2016年 | 212篇 |
2015年 | 164篇 |
2014年 | 265篇 |
2013年 | 341篇 |
2012年 | 142篇 |
2011年 | 188篇 |
2010年 | 270篇 |
2009年 | 378篇 |
2008年 | 191篇 |
2007年 | 138篇 |
2006年 | 166篇 |
2005年 | 155篇 |
2004年 | 112篇 |
2003年 | 107篇 |
2002年 | 83篇 |
2001年 | 158篇 |
2000年 | 129篇 |
1999年 | 162篇 |
1998年 | 192篇 |
1997年 | 213篇 |
1996年 | 317篇 |
1995年 | 268篇 |
1994年 | 203篇 |
1993年 | 129篇 |
1992年 | 148篇 |
1991年 | 162篇 |
1990年 | 103篇 |
1989年 | 166篇 |
1988年 | 141篇 |
1987年 | 114篇 |
1986年 | 136篇 |
1985年 | 117篇 |
1984年 | 120篇 |
1983年 | 99篇 |
1982年 | 84篇 |
1981年 | 82篇 |
1980年 | 85篇 |
1979年 | 65篇 |
1978年 | 73篇 |
1977年 | 55篇 |
1976年 | 54篇 |
1975年 | 65篇 |
1972年 | 51篇 |
1971年 | 57篇 |
排序方式: 共有8071条查询结果,搜索用时 15 毫秒
1.
2.
Prevalence of vitamin D depletion among morbidly obese patients seeking gastric bypass surgery 总被引:5,自引:0,他引:5
Arthur M. Carlin M.D. D. Sudhaker Rao MB B.S. F.A.C.P. F.A.C.E. Ali M. Meslemani M.D. Jeffrey A. Genaw M.D. Nayana J. Parikh Shiri Levy M.D. Arti Bhan M.D. Gary B. Talpos M.D. 《Surgery for obesity and related diseases》2006,2(2):696-103
BACKGROUND: Abnormalities in calcium and vitamin D metabolism have been reported after bariatric surgery. The purpose of this study was to evaluate vitamin D nutritional status among morbidly obese patients before gastric bypass surgery. METHODS: We prospectively studied 279 morbidly obese patients seeking gastric bypass surgery for vitamin D nutritional status as assessed by serum 25-hydroxyvitamin D level. In addition, serum samples were analyzed for calcium, alkaline phosphatase (AP), intact parathyroid hormone (PTH), and 1,25-dihydroxyvitamin D. RESULTS: Mean patient age was 43 +/- 9 years; 87% of the study patients were women, and 72% were white. Serum calcium and AP levels were normal in 88% and 89% of the patients, respectively. Vitamin D depletion, defined as serum 25-hydroxyvitamin D level 相似文献
3.
4.
5.
Harold C. Lyon Jr. James C. Healy James R. Bell Joseph F. O'Donnell Edward K. Shultz Robert S. Wigton Frank Hirai J. Robert Beck 《Journal of medical systems》1991,15(2):117-132
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
6.
7.
LESLEY BOULTON MB CHB FRACO DO Ophthalmologist 《Clinical & experimental ophthalmology》1986,14(4):365-371
The Low Vision Clinic at the Palmerston North Hospital has now been oerating for 70 years. Over the course of these ten years a number of factors have emerged which can be as readily applied to general ophthalmological practice as to low vision practice. The philosophy of low vision care is one of which all ophthalmologists should be aware and includes factors to be taken into account when dealing with children, people in the workplace, and everyday factors involved in daily living activities, all of which are equally relevant in routine ophthalmological practice. This paper endeavours to share some thoughts on these factors and also discusses means by which the visually handicapped can be helped in areas where specialist low vision services are not readily available. 相似文献
8.
Comparison of trichloroethylene and enflurane as adjuncts to nitrous oxide and relaxant anaesthesia 总被引:1,自引:0,他引:1
Forty women who underwent gynaecological surgery were randomly allocated to receive trichloroethylene, enflurane, or enflurane plus fentanyl as adjuncts to nitrous oxide/relaxant anaesthesia with controlled ventilation. No serious cardiac dysrhythmias were seen in any group. Each patient was observed postoperatively for 4 hours by a nurse blind to the technique used, and questioned at 24 hours by a similarly blinded anaesthetist. Recovery after trichloroethylene was not significantly prolonged although postoperative analgesia by visual analogue was better, opiate analgesia was required less frequently and there was less nausea and vomiting than in either of the enflurane groups. We argue for the continued use of trichloroethylene by this technique, because it costs one hundred times less than enflurane and because of the potential morbidity of the postoperative opiate dosage required after enflurane. 相似文献
9.
E.Paul Kirk MB BS J. Santa MD T. Heckler MBA M. Collins MD 《American journal of obstetrics and gynecology》1998,178(6):1222-1228
OBJECTIVE: Our purpose was to assess whether legislative action influenced the role of obstetrician-gynecologists as primary care physicians. STUDY DESIGN: An observational study was performed on the basis of a questionnaire sent to 410 obstetrician-gynecologists and 27 medical directors of managed-care organizations. RESULTS: Of 67% of obstetrician-gynecologists and 96% of medical directors who responded, there was agreement as to the content of primary care, but a minority (38%) of obstetrician-gynecologists identified themselves as primary care providers. A minority of medical directors (35%) felt that obstetrician-gynecologists should serve in that role. Both obstetrician-gynecologists and medical directors felt that legislation had little impact. CONCLUSION: The reticence of obstetrician-gynecologists to assume a major role in primary care appears to be the result of an uneasiness with accepting a more comprehensive role in patient management and gatekeeping. They appear comfortable with the more traditional roles but feel that training and experience has not prepared them well for the management of more complex medical problems. (Am J Obstet Gynecol 1998;178:1222-8.) 相似文献
10.