全文获取类型
收费全文 | 2376篇 |
免费 | 174篇 |
国内免费 | 39篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 161篇 |
妇产科学 | 24篇 |
基础医学 | 236篇 |
口腔科学 | 80篇 |
临床医学 | 216篇 |
内科学 | 670篇 |
皮肤病学 | 60篇 |
神经病学 | 42篇 |
特种医学 | 336篇 |
外科学 | 284篇 |
综合类 | 22篇 |
预防医学 | 112篇 |
眼科学 | 24篇 |
药学 | 170篇 |
1篇 | |
中国医学 | 1篇 |
肿瘤学 | 145篇 |
出版年
2023年 | 14篇 |
2022年 | 15篇 |
2021年 | 31篇 |
2020年 | 17篇 |
2019年 | 32篇 |
2018年 | 46篇 |
2017年 | 36篇 |
2016年 | 43篇 |
2015年 | 55篇 |
2014年 | 68篇 |
2013年 | 89篇 |
2012年 | 62篇 |
2011年 | 74篇 |
2010年 | 76篇 |
2009年 | 104篇 |
2008年 | 85篇 |
2007年 | 98篇 |
2006年 | 92篇 |
2005年 | 81篇 |
2004年 | 66篇 |
2003年 | 70篇 |
2002年 | 53篇 |
2001年 | 57篇 |
2000年 | 52篇 |
1999年 | 48篇 |
1998年 | 104篇 |
1997年 | 120篇 |
1996年 | 120篇 |
1995年 | 79篇 |
1994年 | 85篇 |
1993年 | 103篇 |
1992年 | 28篇 |
1991年 | 26篇 |
1990年 | 24篇 |
1989年 | 55篇 |
1988年 | 53篇 |
1987年 | 36篇 |
1986年 | 35篇 |
1985年 | 40篇 |
1984年 | 27篇 |
1983年 | 18篇 |
1982年 | 20篇 |
1981年 | 35篇 |
1980年 | 21篇 |
1979年 | 10篇 |
1978年 | 9篇 |
1977年 | 23篇 |
1976年 | 20篇 |
1975年 | 6篇 |
1968年 | 4篇 |
排序方式: 共有2589条查询结果,搜索用时 15 毫秒
1.
Birth weight on 12,644 singleton infants from 6,196 sibships born in Maryland between 1980 and 1984 were used to estimate the effects of nine maternal and infant covariates on the sibship correlation in birth weight. Assuming a homogeneous correlation across all families, the estimated intraclass correlation was 0.4664 (+/- 0.0099). This high sibship correlation makes it possible to predict, with reasonable accuracy, the birth weight of a child given information on previous sibs, as well as covariates on the mother and/or infant pertinent to a given pregnancy. The reduction in variance associated with incorporating information on the nine covariates used here was approximately equal to that obtained by conditioning on a single previous sib. Testing for heterogeneity in correlation among different groups of families showed that a crude measure of parity (first live birth vs. other), time between births, mother's marital status, and maternal age at the birth of the last child significantly influenced the sibship correlation in birth weight. 相似文献
2.
CM Reid M. Nelson P. Beckinsale P. Ryan LMH Wing LJ Beilin MA Brown GLR Jennings CI Johnston J. Marley JJ McNeil TO Morgan J. Shaw ID Steven MJ West 《Clinical and experimental pharmacology & physiology》1997,24(5):370-373
1. The present study aimed to determine the feasibility of conducting a 5 year cardiovascular outcome trial of the treatment of 6000 elderly hypertensive patients in Australian general practices. 2. General practitioners (GPs) were invited to participate by mail and personal follow-up. Patient records were reviewed to identify subjects for a blood pressure (BP) screening programme. Blood pressure was measured on three occasions and eligible subjects were included if the average BP was 160 mmHg systolic or 90 mmHg diastolic if systolic BP was 140 mmHg. 3. Seven hundred and forty-one GPs were approached and 89 were enrolled in the study (12% of mail invites and 75% of those receiving a personal contact). In 16 practices where screening was completed, 82 000 records were reviewed to identify 4% patients eligible for screening. Twenty-two per cent of eligible subjects attended screening. Of 1938 subjects screened, 180 (9%) had BP 5=160/90 mmHg. Forty-seven percent of subjects (n = 916) were receiving antihypertensive therapy and 184 (20%) were withdrawn from therapy. One hundred and sixteen (63%) of these subjects had BP return to study entry levels within 6 weeks. Fifty-seven newly diagnosed and 81 previously treated subjects were randomized (7% of the screened population). 4. Based on the high participation rate of GPs, the response rate of patients to attend a BP screening programme and the 7% randomization to screening ratio for entry into the study, the ANBP2 pilot study has demonstrated that it is feasible to recruit subjects from Australian general practices to a cardiovascular outcome trial. 相似文献
3.
LN Weinberger MJ Zirwas JC English III 《Journal of the European Academy of Dermatology and Venereology》2007,21(2):156-162
Male genital oedema can be defined as swelling or the appearance of swelling of the scrotum and/or the penile shaft and prepuce. Despite the various causes of genital oedema reported in the published work, a concise approach to the evaluation and management has not been sufficiently addressed. 相似文献
4.
Lipodermatosclerosis: review of cases evaluated at Mayo Clinic. 总被引:1,自引:0,他引:1
Alison J Bruce Daniel D Bennett Christine M Lohse Thom W Rooke Mark D P Davis 《Journal of the American Academy of Dermatology》2002,46(2):187-192
BACKGROUND: Lipodermatosclerosis describes bound-down, sclerotic skin involving the lower extremities. OBJECTIVE: Our purpose was to describe the demographic and clinical features of patients with lipodermatosclerosis. METHODS: This was a retrospective study of patients presenting to Mayo Clinic between 1976 and 1998 with a diagnosis of lipodermatosclerosis. RESULTS: Of 97 patients, 84 (87%) were women. Mean age was 62 years (range, 25-88 years). Mean body mass index was 34.3 (range, 17.8-71.5). Clinical signs were bilateral involvement in 44 patients (45%), induration localized to a discrete plaque in 49 (51%), erythema in 69 (71%), hyperpigmentation in 57 (59%), ulceration in 13 (13%), concomitant edema in 69 (71%), and varicosities in 55 (57%). Vascular studies performed on 72 patients showed abnormalities in 49: deep venous incompetence in 33 (67%), calf muscle pump abnormality in 19 (39%), abnormal pulsatility in 10 (20%), and obstruction in 1 (2%). CONCLUSION: Lipodermatosclerosis was associated with female sex, middle age, high body mass index, and venous abnormalities. 相似文献
5.
Schramm C Huber S Protschka M Czochra P Burg J Schmitt E Lohse AW Galle PR Blessing M 《International immunology》2004,16(9):1241-1249
6.
Induction of the anti-ergotypic response 总被引:1,自引:0,他引:1
Lohse A. W.; Spahn T. W.; Wolfel T.; Herkel J.; Cohen I. R.; Buschenfelde K. H. Meyer zum 《International immunology》1993,5(5):533-539
The injection of syngeneic activated T cells into rodents caninduce a T cell response against activation markers of the Tcells, ergotopes. The responding antl-ergotypic T cells havebeen shown to suppress experimental autoimmune encephalomyelitis(EAE). This paper reports the characteristics of the antl-ergotypicresponse. It was found that irradiated activated T cells wereas good as untreated living activated T cells in inducing anti-ergotypiccells in vivo. Glutardialdehyde-fixed (0.3%) cells were poorstimulators in vivo and non-stimulatory in vitro. Dilution ofglutardialdehyde to 0.003% before fixation preserved the stimulatorycapacity in vitro. Fixation or irradiation of T cells at differenttimes after activation showed that the stimulatory ergotopeappears only after more than 12 h of activation. This ergotopeis not secreted by activated T cells, but is a structural componentof the activated T cell. Injection of solubilized proteins fromactivated T cells, but not of supernatants from activated Tcells, was able to induce an anti-ergotypic response in vivo.In vitro supernatants from activated T cells also were not stimulatoryto anti-ergotypic T cells. The anti-ergotypic response couldbe measured in draining lymph nodes 3 days after injection,reached a maximum after 7–10 days and subsided thereafter.It was earlier and stronger than the anti-ldiotypic response.Induction of the response was dose dependent. As few as 100cells were able to induce a marked anti-ergotypic response.The ease of the induction and the strength of the anti-ergotypicresponse suggest a physiological role in immunoregulatlon. 相似文献
7.
Rigor and resistance to stretch in vertebrate smooth muscle 总被引:2,自引:0,他引:2
8.
9.
Zusammenfassung An 21 Patienten wurde die Harnschwelle für Zucker, die tubuläre Rückresorptionskapazität und die Zuckerausscheidung bestimmt. Hierbei ergab sich bei langdauernder Zuckerbelastung eine absolute Vergrößerung der ausgeschiedenen Zukkermengen mit Abfall der Harnzuckerschwelle. Diese Verminderung wurde durch einen absoluten Abfall der tubulären Rückresorptionskapazität und relativen Abfall im Verhältnis zur filtrierten Zuckermenge hervorgerufen. Diese Einschränkungen traten mit zunehmender Versuchsdauer in Erscheinung und werden auf eine Erschöpfung der tubulären fermentativen Vorgänge bezogen. Vielleicht finden hierin auch die anderweitig beobachteten tubulären Degenerationen bei langdauernder Zuckerbelastung ihre Erklärung. Eine länger dauernde Glykosurie scheint für die Tubulusepithelien eine echte Belastung darzustellen.Diese Arbeit ist meinem Chef, Herrn Prof.Wollheim, zu seinem 60. Geburtstag am 24. 3. 60 gewidmet. 相似文献
10.
Martin J. Lohse Dieter Ukena Ulrich Schwabe 《Naunyn-Schmiedeberg's archives of pharmacology》1985,328(3):310-316
Summary Adenosine has been shown to have negative inotropic, chronotropic and dromotropic effects on the heart. The pharmacological profiles of these effects suggest that they are mediated via Ri (A1) adenosine receptors, but a direct demonstration of these receptors is still missing. In the present study we report direct labelling of these receptors with (-)N6-[125I]-p-hydroxyphenylisopropyladenosine ([125I]HPIA). The radioligand bound in a saturable and reversible manner to a crude membrane preparation, the B
max-value was 30.5 fmol/mg protein and the K
D-value 1.1 nmol/l. A similar affinity of the ligand was obtained in kinetic and competition experiments. Competition experiments with a variety of adenosine analogues gave a pharmacological profile characteristic of Ri adenosine receptors with high affinities of N6-substituted derivatives and a marked stereospecificity for N6-phenylisopropyladenosine (PIA). Purification of the membrane preparation by density gradient centrifugation resulted in a 30-fold increase in the number of binding sites which was paralleled by a similar increase in the number of binding sites for [3H]ouabain. Guanine nucleotides decreased binding of [125I]HPIA in a dose-dependent manner, but the IC50-values were considerably higher than those reported in other tissues. Finally, binding of [125I]HPIA appeared to be entropy-driven which has been shown to be characteristic of agonist binding to Ri adenosine receptors. These results suggest the presence of Ri adenosine receptors in ventricular myocardium which may be responsible for the mediation of the effects of adenosine and its analogues.Abbreviations [125I]HPIA
(-)N6-[125I]-p-hydroxyphenylisopropyladenosine
- (-)IHPIA
(-)N6-iodo-p-hydroxyphenylisopropyladenosine
- (+)/(-)PIA
(+)/(-)N6-phenylisopropyladenosine
- CHA
N6-cyclohexyladenosine
- NECA
5-N-ethylcarboxamidoadenosine
- App(NH)p
5-adenylylimidodiphosphate
- Gpp(NH)p
5-guanylylimidodiphosphate 相似文献