全文获取类型
收费全文 | 17326篇 |
免费 | 1748篇 |
国内免费 | 74篇 |
专业分类
耳鼻咽喉 | 144篇 |
儿科学 | 592篇 |
妇产科学 | 529篇 |
基础医学 | 2508篇 |
口腔科学 | 287篇 |
临床医学 | 2075篇 |
内科学 | 3419篇 |
皮肤病学 | 235篇 |
神经病学 | 1307篇 |
特种医学 | 804篇 |
外国民族医学 | 3篇 |
外科学 | 2031篇 |
综合类 | 384篇 |
一般理论 | 11篇 |
预防医学 | 1931篇 |
眼科学 | 367篇 |
药学 | 1340篇 |
中国医学 | 14篇 |
肿瘤学 | 1167篇 |
出版年
2021年 | 213篇 |
2020年 | 152篇 |
2019年 | 243篇 |
2018年 | 267篇 |
2017年 | 208篇 |
2016年 | 234篇 |
2015年 | 249篇 |
2014年 | 348篇 |
2013年 | 548篇 |
2012年 | 706篇 |
2011年 | 782篇 |
2010年 | 488篇 |
2009年 | 437篇 |
2008年 | 674篇 |
2007年 | 742篇 |
2006年 | 644篇 |
2005年 | 680篇 |
2004年 | 661篇 |
2003年 | 660篇 |
2002年 | 576篇 |
2001年 | 546篇 |
2000年 | 561篇 |
1999年 | 471篇 |
1998年 | 265篇 |
1997年 | 240篇 |
1996年 | 248篇 |
1995年 | 227篇 |
1994年 | 200篇 |
1993年 | 194篇 |
1992年 | 420篇 |
1991年 | 415篇 |
1990年 | 428篇 |
1989年 | 384篇 |
1988年 | 408篇 |
1987年 | 393篇 |
1986年 | 361篇 |
1985年 | 330篇 |
1984年 | 265篇 |
1983年 | 228篇 |
1982年 | 135篇 |
1979年 | 225篇 |
1978年 | 183篇 |
1977年 | 151篇 |
1976年 | 163篇 |
1975年 | 164篇 |
1974年 | 155篇 |
1973年 | 177篇 |
1972年 | 142篇 |
1971年 | 129篇 |
1970年 | 138篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
42.
Resuscitation training for medical students and junior doctors in the United Kingdom and United States was compared using questionnaires sent to medical schools in both countries. A marked deficiency in the provision of cardiopulmonary resuscitation training has been demonstrated in the United Kingdom; however, in the United States, the availability of uniform certifiable teaching is now widespread. Suggestions for the improvement of training in the United Kingdom are expected to increase medical student proficiency in cardiopulmonary resuscitation. The need for training in basic and advanced resuscitation prior to graduation from medical school is stressed. 相似文献
43.
Alan M. Mellow Trey Sunderland Robert M. Cohen Brian A. Lawlor James L. Hill Paul A. Newhouse Martin R. Cohen Dennis L. Murphy 《Psychopharmacology》1989,98(3):403-407
Thyrotropin releasing hormone (TRH) was administered intravenously to ten patients with Alzheimer's Disease (AD) in a high-dose paradigm, thought to maximize central nervous system effects and potentially produce facilitation of cholinergic function, a known property of the neuropeptide. Acute effects of TRH on behavioral, cognitive and physiologic measures were assessed after patients received 0.1 mg/kg TRH, 0.3 mg/kg TRH and placebo, the higher TRH dose and placebo being given in a randomized, double-blind fashion. Patients showed statistically significant increases in arousal and improvement in affect, as well as a modest improvement in semantic memory, all after receiving the higher TRH dose. Both TRH doses produced transient rises in systolic blood pressure, with no effect on diastolic blood pressure, heart rate or temperature. This study suggests that high-dose TRH can be safely administered to AD patients and is neurobehaviorally active; further studies are needed to determine the extent and mechanism of the cognitive and psychobiological properties of this peptide in AD and other neuropsychiatric disorders. 相似文献
44.
Regulation of G proteins by chronic antidepressant drug treatment in rat brain: tricyclics but not clorgyline increase Go alpha subunits. 总被引:4,自引:0,他引:4
K P Lesch C S Aulakh T J Tolliver J L Hill D L Murphy 《European journal of pharmacology》1991,207(4):361-364
The effect of long-term (3-week) administration of various antidepressant drugs on the steady-state concentrations of G protein alpha subunits, Gs alpha, Gi alpha, and Go alpha, has been investigated in rat brain using an enzyme-linked immunosorbent assay. Tricyclic antidepressants and clorgyline decreased Gs alpha and, to a lesser extent, Gi alpha in several brain regions, while Go alpha was increased by tricyclics but not clorgyline. We conclude that long-term treatment with antidepressant drugs exerts differential effects on G protein alpha subunits, and that antidepressant efficacy may potentially be based on functional modifications of signal transduction. 相似文献
45.
G H Rao V John T D Hill J L Vennerstrom J G White T J Holmes 《Thrombosis research》1986,44(4):527-538
The present study has evaluated the effect of some newly synthesized triphenylethylene (TPE) analogs on platelet arachidonic acid metabolism and function. All compounds tested inhibited arachidonic acid induced platelet aggregation and several were superior to aspirin in their relative potency. Introduction of a carboxyl function into the alpha-ring, which should enhance binding according to proposed structural models for cyclooxygenase inhibitors, was not found to be beneficial. Increased structural rigidity, which resulted from covalent linkage of two aromatic rings in this series, did not eliminate anti-aggregatory properties. 相似文献
46.
47.
Does atopy have any predictive value for laboratory animal allergy? A comparison of different concepts of atopy 总被引:2,自引:0,他引:2
Atopy is widely used as a discriminant in selection for employment involving exposure to allergenic substances. The validity of this has been tested in a population with a known burden of what is largely considered to be an IgE mediated disease, laboratory animal allergy. The findings suggest that atopy is insufficiently sensitive and specific for this purpose and that this is probably true for other occupational allergic diseases. The relation between different concepts of atopy--namely, atopy defined by family history, by personal history, and by skin prick tests with common allergens--has also been examined. The subpopulations identified by these criteria differed appreciably. Different concepts of atopy should not be used synonymously as they often are at present. 相似文献
48.
OBJECTIVE: Screening colonoscopy has been shown to reduce mortality and cancer stage in hereditary nonpolyposis colorectal cancer (HNPCC) individuals. However, the benefit of screening in intermediate risk groups is unknown. The most recent national guidelines have recommended a reduction of screening frequency for the intermediate risk group. Therefore, this study aims to compare the results of colonoscopic screening in HNPCC and intermediate risk groups and assess the effect of the most recent screening protocol recommendations. METHOD: A total of 244 individuals; 108 from HNPCC families (28 mismatch repair gene carriers) and 136 from intermediate risk families were referred for regular colonoscopic screening by the Regional Genetics Service. Findings from 417 colonoscopies performed between 1992 and 2003 were evaluated. RESULTS: A total of three cancers, 39 adenomas and 41 hyperplastic polyps were found in the HNPCC group compared with one cancer, 22 adenomas and 19 hyperplasic polyps in the intermediate risk group. If the recent screening guidelines for the intermediate group were applied, then 89 (44%) fewer colonoscopies would have been performed. Although no cancers would have been missed, six adenomas (mean size = 5.7 mm, range 2-10 mm) with two graded as severely dysplasic and six hyperplastic polyps would not have been detected. CONCLUSION: The detection rate and distribution of adenomas were similar in both groups. If the new colonoscopic screening recommendations for the intermediate risk group had been applied, a small number of significant lesions would have been missed. 相似文献
49.
Context Residents in all disciplines serve as clinical teachers for medical students. Since the 1970s, there has been increasing evidence to demonstrate that residents wish to teach and that they respond positively to formal teacher training. Effective resident‐as‐teacher (RaT) programmes have resulted in improved resident teaching skills. Current evidence, however, is not clear about the specific features of an effective RaT programme. Objectives This study was performed in order to investigate the effectiveness of RaT programmes on resident teaching abilities and to identify the features that ensure success. Methods of assessment used to ascertain the effectiveness of RaT programmes are also explored. Methods The literature search covered the period between 1971 and 2008. Articles focusing on improving resident teaching skills were included. Each study was reviewed by two reviewers and data were collected using a standard abstraction summary sheet. Study outcomes were graded according to a modified Kirkpatrick's model of educational outcomes. Results Twenty‐nine studies met review inclusion criteria. Interventions included workshops, seminars, lectures and teaching retreats. Twenty‐six studies used a pre‐ and post‐intervention outcome comparison method. Subjective outcome measures included resident self‐evaluation of teaching skills or evaluation by medical students, peers and faculty members. Objective outcome measures included written tests, evaluation of teaching performance by independent raters and utilisation of objective structured teaching examinations. One study objectively measured learning outcomes at the level of medical students, utilising the results of an objective structured clinical examination. Overall resident satisfaction with RaT programmes was high. Participants reported positive changes in attitudes towards teaching. Participant knowledge of educational principles improved. Study methodologies allowed for significant risks of bias. Conclusions More rigorous study designs and the use of objective outcome measures are needed to ascertain the true effectiveness of RaT programmes. Future research should focus on determining the impact of RaT programmes on learning achievement at the level of medical students. 相似文献
50.
JC Sitek† M Loeb‡ JR Ronnevig¶ 《Journal of the European Academy of Dermatology and Venereology》2007,21(7):891-896
BACKGROUND: Since 1997, a number of trials have shown promising results in treating generalized vitiligo with narrowband ultraviolet B (UVB) both in adults and children. However, there is little knowledge concerning the duration and permanency of the treatment-induced repigmentation. OBJECTIVE: Our main objective was to perform a follow-up trial of successfully treated patients receiving narrowband UVB for generalized vitiligo. METHODS: We have investigated to what degree the treatment-induced repigmentation remains stable for up to 2 years post-treatment. We performed an initial open trial including 31 patients with generalized vitiligo. They received narrowband UVB thrice weekly for up to 12 months. Patients experiencing > 75% repigmentation were defined responders and were included in the follow-up trial. Responders were followed every 6 months for up to 2 years after cessation of treatment. We observed the pigmentation status and registered any changes indicating loss of pigmentation and relapse. RESULTS: Eleven of the 31 treated patients were included in the follow-up trial. Six patients had relapse and five patients had stable response 24 months after cessation of treatment. Four out of six relapses were within 6 months post-treatment. CONCLUSION: In our study population of 31 patients with generalized vitiligo, five patients (16%) experienced > 75% stable repigmentation 2 years after cessation of a treatment programme of up to 1 years narrowband UVB therapy. 相似文献