全文获取类型
收费全文 | 6873篇 |
免费 | 722篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 116篇 |
儿科学 | 189篇 |
妇产科学 | 173篇 |
基础医学 | 861篇 |
口腔科学 | 105篇 |
临床医学 | 1021篇 |
内科学 | 1274篇 |
皮肤病学 | 78篇 |
神经病学 | 595篇 |
特种医学 | 392篇 |
外科学 | 746篇 |
综合类 | 107篇 |
预防医学 | 827篇 |
眼科学 | 126篇 |
药学 | 565篇 |
中国医学 | 10篇 |
肿瘤学 | 424篇 |
出版年
2021年 | 95篇 |
2020年 | 63篇 |
2019年 | 86篇 |
2018年 | 128篇 |
2017年 | 91篇 |
2016年 | 95篇 |
2015年 | 132篇 |
2014年 | 143篇 |
2013年 | 202篇 |
2012年 | 288篇 |
2011年 | 292篇 |
2010年 | 205篇 |
2009年 | 207篇 |
2008年 | 267篇 |
2007年 | 298篇 |
2006年 | 275篇 |
2005年 | 269篇 |
2004年 | 234篇 |
2003年 | 262篇 |
2002年 | 227篇 |
2001年 | 205篇 |
2000年 | 238篇 |
1999年 | 224篇 |
1998年 | 131篇 |
1997年 | 124篇 |
1996年 | 129篇 |
1995年 | 96篇 |
1994年 | 85篇 |
1993年 | 107篇 |
1992年 | 172篇 |
1991年 | 179篇 |
1990年 | 177篇 |
1989年 | 191篇 |
1988年 | 176篇 |
1987年 | 155篇 |
1986年 | 155篇 |
1985年 | 130篇 |
1984年 | 88篇 |
1983年 | 80篇 |
1982年 | 77篇 |
1981年 | 72篇 |
1980年 | 65篇 |
1979年 | 67篇 |
1978年 | 53篇 |
1977年 | 40篇 |
1976年 | 42篇 |
1975年 | 46篇 |
1974年 | 36篇 |
1973年 | 37篇 |
1972年 | 41篇 |
排序方式: 共有7609条查询结果,搜索用时 0 毫秒
41.
This study examined the acquisition of verb particles and prepositions in language-impaired, language-matched, and age-matched preschool children. A videotape experimental task, in which subjects viewed and described brief action sequences, was implemented. The videotape task included particle, preposition, full noun phrase, and pronoun noun phrase items for six different particle/preposition words. Primary results indicated that the use of verb particles constituted a particularly challenging linguistic task for the language-impaired subjects relative to both their age- and language-matched peers. These results suggest multiple sources of difficulty for language-impaired children in the acquisition of grammatical form classes. Lexical and grammatical difficulties, as well as possible processing limitations, are implicated. 相似文献
42.
43.
Does altered biomechanics cause marrow edema? 总被引:21,自引:0,他引:21
44.
45.
The epidemiology of traumatic rupture of the thoracic aorta in children: a 13-year review 总被引:1,自引:0,他引:1
A C Eddy V W Rusch C L Fligner D T Reay C L Rice 《The Journal of trauma》1990,30(8):989-91; discussion 991-2
Traumatic rupture of the thoracic aorta (TRA) is a rare but highly lethal injury in children that occurs as a result of car versus pedestrian accidents and motor vehicle accidents. TRA is often associated with life-threatening injuries to other organ systems. Therefore children with TRA like adults sustaining TRA must be treated urgently but systematically. The rarity of this injury makes it all the more important for physicians treating pediatric trauma victims to be cognizant of the importance of the injury and the clinical and radiographic signs. Even when TRA is promptly recognized in children it is associated with a high in-hospital mortality. The proper use of child restraint systems and adherence to the 55 M.P.H. speed limit may be important factors in reducing the mortality of TRA in children after MVA. 相似文献
46.
There are three principal malignant vasoformative tumors that can be found in the head and neck--hemangiopericytoma, angiosarcoma, and Kaposi's sarcoma. All are uncommon and provide challenges for the pathologist and the therapist both. The histogenesis of each tumor is different. Kaposi's sarcoma has many features which suggest that it is an altered immune-response disease. Angiosarcoma is a malignancy of endothelium. Hemangiopericytoma is a tumor whose cell of origin is considered to be the perithelial pericyte. The general prognosis for patients with Kaposi's sarcoma is good. The biologic course of a hemangiopericytoma is variable and unpredictable, but there appears to be a site dependency. Angiosarcomas, particularly high grade lesions, are resistant to therapy. 相似文献
47.
48.
R B Rothman V Bykov A Reid B R De Costa A H Newman A E Jacobson K C Rice 《Neuropeptides》1988,12(3):181-187
Norbinaltorphimine (nor-BNI) is a bifunctional reagent developed as a selective antagonist of the kappa opioid receptor. In this paper we examined the in vitro selectivity of nor-BNI, 6-desoxy-6 beta-fluoronaltrexone (cycloFOXY), and the enantiomer of cycloFOXY, among opioid receptor subtypes. Nor BNI exhibited the highest affinity for kappa binding sites labeled by 3H-U69593 (Ki = 1.8nM), and was 27- to 29-fold less potent at mu and delta binding sites. In contrast, cycloFOXY had the highest affinity for mu binding sites (Ki = 2.62 nM), and bound to kappa and delta binding sites with Ki's of 9.3 nM and 89 nM, respectively. The enantiomer of cycloFOXY, did not inhibit binding even at concentrations greater than 10 microM, validating in part the use of 18F-labeled (+)-cycloFOXY to estimate "non-specific binding" in positron emission tomography. Additionally, we report that (S,S)-U50 488 and (R.R)-U50 488 bind to kappa binding sites labeled by 3H-U69 593 with Ki's of 0.89 nM and 299 nM, respectively. 相似文献
49.
Carol Smillie B.N. B.Ed. M.S.C. Katherine Coffin B.A. ME.D. Kathryn Porter B.A. Brenda Ryan B.A. M.B.A. 《Journal of community health》1988,13(3):156-170
The International Conference on Primary Health Care, meeting in Alma-Ata, in the Soviet Union, September 12, 1978, expressed the need for urgent action by all governments, all health and development workers and the world community, to protect and promote the health of all people of the world. The world was caught by the phrase which emerged from this conference, Health For All by the Year 2000 and many have examined the articles of the Alma-Ata declaration and tried to implement them in their corner of the world. This paper describes a community-based smoking-cessation program which was implemented in the province of Nova Scotia, Canada, during the years 1980–1984. Primary to this project was the belief that people have the right and the duty to participate individually and collectively in planning and implementing their health care. This paper describes one community's effort in putting this belief into practice.Carol Smillie, B.N. BE.d. M.S.c. is an Assistant Professor at the School of Nursing, Dalhousie University, Halifax, Nova Scotia, Canada B3H 3J5, Katherine Coffin, BA, MEd is the Program Officer, Nova Scotia Office, Health Promotion Directorate Health and Welfare Canada, 5251 Duke Street, Halifax, Nova Scotia. Canada B3J 1P3. Kathryn Porter, B.A. (Gen)., is the Information and Education Coordinator, Nova Scotia Division Canadian Cancer Society. Brenda Ryan, B.A., M.B.A. is Program Evaluation Analysist, Nova Scotia Department of Health, 6088 Hollis Street, Halifax. Nova Scotia, Canada. This Project was funded by Health and Welfare Canada, Nova Scotia Department of Health, Nova Scotia Division Canadian Cancer Society, Requests for reprints should be addressed to: Professor Carol Smillie. 相似文献
50.
J P Rice N Rochberg J Endicott P W Lavori C Miller 《Archives of general psychiatry》1992,49(10):824-830
In the National Institute of Mental Health Collaborative Program on the Psychobiology of Depression study, data were collected on 2226 first-degree relatives of 612 probands. A second, "blind" reassessment of all relatives was attempted 6 years after the initial evaluation. We report on a final sample of 1629 relatives assessed twice using the Schedule for Affective Disorders and Schizophrenia-Lifetime version. We summarize methods for using stability of diagnosis to model the relationship between clinical covariates and the probability of being a true case. Moreover, we define an index of caseness that can be used to narrow the criteria for who is a case. Of those positive for major depressive disorder at initial evaluation, 74% were positive (on a lifetime basis) at follow-up (ie, were stable). There is a gradient: 48% of those who had three symptoms and no treatment were stable, compared with 96% of those with eight symptoms and treatment. For major depressive disorder, we found the caseness index for those with lifetime mania more severe than that of nonbipolar patients, with those who had hypomania being intermediate. A hierarchical analysis indicated that bipolar I tends to be diagnosed as schizoaffective-manic across occasions, and vice versa. This is consistent with the prior familial analyses that suggest these two diagnoses be combined into a single bipolar phenotype. The analysis for major depressive disorder indicates that caseness appears to represent quantitative, rather than qualitative, differences, with no natural cutoff to identify distinct subgroups. Finally, we discuss implications including utility in genetic analyses, estimation of incidence or prevalence allowing for diagnostic error, and examination of cohort effects. 相似文献