全文获取类型
收费全文 | 9338篇 |
免费 | 689篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 90篇 |
儿科学 | 287篇 |
妇产科学 | 175篇 |
基础医学 | 1183篇 |
口腔科学 | 127篇 |
临床医学 | 1321篇 |
内科学 | 1875篇 |
皮肤病学 | 134篇 |
神经病学 | 775篇 |
特种医学 | 247篇 |
外科学 | 1027篇 |
综合类 | 122篇 |
一般理论 | 4篇 |
预防医学 | 1150篇 |
眼科学 | 89篇 |
药学 | 572篇 |
中国医学 | 3篇 |
肿瘤学 | 866篇 |
出版年
2023年 | 82篇 |
2022年 | 111篇 |
2021年 | 281篇 |
2020年 | 142篇 |
2019年 | 229篇 |
2018年 | 249篇 |
2017年 | 180篇 |
2016年 | 194篇 |
2015年 | 197篇 |
2014年 | 272篇 |
2013年 | 425篇 |
2012年 | 629篇 |
2011年 | 636篇 |
2010年 | 331篇 |
2009年 | 350篇 |
2008年 | 518篇 |
2007年 | 584篇 |
2006年 | 575篇 |
2005年 | 573篇 |
2004年 | 516篇 |
2003年 | 455篇 |
2002年 | 423篇 |
2001年 | 173篇 |
2000年 | 167篇 |
1999年 | 139篇 |
1998年 | 89篇 |
1997年 | 75篇 |
1996年 | 85篇 |
1995年 | 76篇 |
1994年 | 62篇 |
1993年 | 70篇 |
1992年 | 91篇 |
1991年 | 75篇 |
1990年 | 89篇 |
1989年 | 70篇 |
1988年 | 82篇 |
1987年 | 67篇 |
1986年 | 58篇 |
1985年 | 55篇 |
1984年 | 64篇 |
1983年 | 53篇 |
1982年 | 36篇 |
1981年 | 34篇 |
1980年 | 24篇 |
1979年 | 48篇 |
1978年 | 28篇 |
1977年 | 28篇 |
1976年 | 23篇 |
1975年 | 22篇 |
1971年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
Anticoagulation for cardiac surgery in patients receiving preoperative heparin: use of the high-dose thrombin time 总被引:1,自引:0,他引:1
Shore-Lesserson L Manspeizer HE Bolastig M Harrington D Vela-Cantos F DePerio M 《Anesthesia and analgesia》2000,90(4):813-818
Patients receiving heparin infusions have an attenuated activated clotting time (ACT) response to heparin given for cardiopulmonary bypass (CPB). We compared patients receiving preoperative heparin (Group H) to those not receiving heparin (REF group) with respect to ACT, high-dose thrombin time (HiTT), and markers of thrombin generation during CPB. Sixty-five consecutive patients (33 Group H, 32 REF group) undergoing elective CPB were evaluated. ACT and HiTT were measured at multiple time points. Plasma levels of thrombin-antithrombin III complex and fibrin monomer were determined at baseline, during CPB, and after protamine administration. Transfusion requirements and postoperative blood loss were measured and compared. ACT values after heparinization increased less in Group H and were significantly lower than those in the REF group (P < 0.01). HiTT values did not differ significantly between the two groups. Blood loss and transfusion requirements were not significantly different between the two groups. Plasma levels of thrombin-antithrombin III complexes and fibrin monomer also did not differ between groups at any time, despite a lower ACT in Group H after heparinization and during CPB. Our data suggest that thrombin formation and activity are not enhanced in patients receiving heparin therapy, despite a diminished ACT response to heparin. The utility of ACT and the threshold values indicative of adequate anticoagulation for CPB are relatively undefined in patients receiving preoperative heparin. HiTT should be investigated as a safe and accurate monitor of anticoagulation for CPB in patients receiving preoperative heparin therapy. Implications: The diminished activated clotting time response to heparin, in patients receiving preoperative heparin therapy, poses difficulties when attempting to provide adequate anticoagulation for cardiopulmonary bypass. Current data suggest that heparin resistance is not observed when high-dose thrombin time is used to monitor anticoagulation and that a lower activated clotting time value in these patients may be safe. 相似文献
102.
103.
104.
105.
Cost containment has captured the attention of health policymakers in most OECD countries, and deliberations about creating powerful financial incentives dominate health care politics. Some European health systems are now implementing hospital payment schemes that mirror the U.S. model of diagnosis-related groups (DRGs) and are raising premiums and copayment levels in an effort to limit public expenditures. Though financial incentives may indeed help rein in health expenditures, focusing predominantly on financial incentives hinders due consideration of needed structural reforms that improve the continuity, quality, and appropriateness of health care service delivery. This article focuses on the structural specifics of two legally enacted health insurance systems (Germany and Austria) and two national health systems (Great Britain and Denmark) to discuss the influence of structural characteristics on cost-containment efforts. Structural reform strategies discussed include increasing reliance on general practitioners, improving coordination of community and hospital-based specialty care, addressing the stark divide between ambulatory and hospital-based care that exists in some European health systems, and improving continuity of care by better integrating medical and social care sectors. Also discussed is the relative focus on financial incentives versus structural deficits in recent European-health care reform strategies. 相似文献
106.
Samuel R. Friedman Barbara Tempalski Hannah Cooper Theresa Perlis Marie Keem Risa Friedman Peter L. Flom 《Journal of urban health》2004,81(3):377-400
This article estimates the population prevalence of current injection drug users (IDUs) in 96 large US metropolitan areas
to facilitate structural analyses of its predictors and sequelae and assesses the extent to which drug abuse treatment and
human immunodeficiency virus (HIV) counseling and testing are made available to drug injectors in each metropolitan area.
We estimated the total number of current IDUs in the United States and then allocated the large metropolitan area total among
large metropolitan areas using four different multiplier methods. Mean values were used as best estimates, and their validity
and limitations were assessed. Prevalence of drug injectors per 10,000 population varied from 19 to 173 (median 60; interquartile
range 42–87). Proportions of drug injectors in treatment varied from 1.0% to 39.3% (median 8.6%); and the ratio of HIV counseling
and testing events to the estimated number of IDUs varied from 0.013 to 0.285 (median 0.082). Despite limitations in the accuracy
of these estimates, they can be used for structural analyses of the correlates and predictors of the population density of
drug injectors in metropolitan areas and for assessing the extent of service delivery to drug injectors. Although service
provision levels varied considerably, few if any metropolitan areas seemed to be providing adequate levels of services. 相似文献
107.
Theresa H M Keegan Sally L Glaser Christina A Clarke Margaret L Gulley Fiona E Craig Joseph A Digiuseppe Ronald F Dorfman Risa B Mann Richard F Ambinder 《Journal of clinical oncology》2005,23(30):7604-7613
PURPOSE: Epstein-Barr virus (EBV) in Hodgkin's lymphoma (HL) cells has been considered as a prognostic marker for this heterogeneous disease, but studies have yielded mixed findings, likely because of selected patient series and failure to acknowledge an effect of age on outcome. This study assessed survival after HL in a population-based cohort large enough to examine the joint effects of EBV with other factors including age, sex, and histologic subtype. PATIENTS AND METHODS: Included were 922 patients with classical HL diagnosed between mid-1988 and 1997 in the Greater San Francisco Bay Area, with archived biopsy specimens assayed for EBV with immunohistochemistry and in situ hybridization. Vital status was followed through December 30, 2003 (median follow-up time, 97 months). Overall and disease-specific survival were analyzed with the Kaplan-Meier method and Cox proportional hazards regression models. RESULTS: In children less than 15 years old, EBV presence was suggestively associated (P = .07) with favorable survival. In adults aged 15 to 44 years, EBV did not affect HL outcome, although a protective effect was suggested. In older adults (45 to 96 years), EBV presence nearly doubled the risk of overall and HL-specific mortality but only for patients with nodular sclerosis (NS) histologic subtype (hazard ratio for death = 2.5; 95% CI, 1.5 to 4.3). CONCLUSION: In HL, EBV tumor cell presence is associated with better survival in young patients and poorer survival in older patients with NS, independent of other factors. Variation in outcome by age and histology could indicate biologically distinct disease entities. Evidence that EBV is a meaningful prognostic marker may have therapeutic relevance. 相似文献
108.
109.
Rachel L. Harrington Dima M. Qato James W. Antoon Rachel N. Caskey Glen T. Schumock Todd A. Lee 《Pediatric blood & cancer》2019,66(6)
Early survivors of pediatric cancer are at increased risk of experiencing chronic conditions; however, little is known about the morbidity burden in this population. In this observational cohort study of commercially insured pediatric cancer survivors in the United States (2009–2014), we find that 22.5% of survivors had one chronic condition, and 36.3% had multiple. Compared with survivors without chronic conditions, the presence of multiple conditions significantly increased the odds of an emergency department visit by 70% (odds ratios [OR], 1.7; 95% confidence interval [CI], 1.4–2.1) and of a hospitalization almost four‐fold (OR, 3.8; 95% CI], 2.5–5.5). Findings are important for informing pediatric survivorship care plans in the years following completion of therapy. 相似文献
110.