全文获取类型
| 收费全文 | 3155534篇 |
| 免费 | 297128篇 |
| 国内免费 | 40048篇 |
专业分类
| 耳鼻咽喉 | 41609篇 |
| 儿科学 | 91064篇 |
| 妇产科学 | 74516篇 |
| 基础医学 | 505598篇 |
| 口腔科学 | 82910篇 |
| 临床医学 | 300170篇 |
| 内科学 | 531552篇 |
| 皮肤病学 | 86477篇 |
| 神经病学 | 264142篇 |
| 特种医学 | 122118篇 |
| 外国民族医学 | 333篇 |
| 外科学 | 477634篇 |
| 综合类 | 156767篇 |
| 现状与发展 | 108篇 |
| 一般理论 | 2095篇 |
| 预防医学 | 251128篇 |
| 眼科学 | 74500篇 |
| 药学 | 233579篇 |
| 441篇 | |
| 中国医学 | 34179篇 |
| 肿瘤学 | 161790篇 |
出版年
| 2022年 | 25176篇 |
| 2021年 | 71570篇 |
| 2020年 | 50378篇 |
| 2019年 | 72970篇 |
| 2018年 | 83928篇 |
| 2017年 | 67571篇 |
| 2016年 | 72076篇 |
| 2015年 | 92461篇 |
| 2014年 | 130214篇 |
| 2013年 | 193268篇 |
| 2012年 | 102141篇 |
| 2011年 | 101612篇 |
| 2010年 | 134055篇 |
| 2009年 | 134876篇 |
| 2008年 | 78303篇 |
| 2007年 | 77506篇 |
| 2006年 | 88172篇 |
| 2005年 | 82711篇 |
| 2004年 | 78239篇 |
| 2003年 | 69044篇 |
| 2002年 | 57251篇 |
| 2001年 | 86737篇 |
| 2000年 | 78423篇 |
| 1999年 | 83040篇 |
| 1998年 | 66594篇 |
| 1997年 | 64743篇 |
| 1996年 | 61197篇 |
| 1995年 | 56559篇 |
| 1994年 | 50187篇 |
| 1993年 | 46402篇 |
| 1992年 | 51715篇 |
| 1991年 | 47999篇 |
| 1990年 | 44535篇 |
| 1989年 | 44811篇 |
| 1988年 | 41256篇 |
| 1987年 | 39906篇 |
| 1986年 | 37530篇 |
| 1985年 | 38107篇 |
| 1984年 | 37399篇 |
| 1983年 | 35024篇 |
| 1982年 | 37712篇 |
| 1981年 | 35824篇 |
| 1980年 | 33781篇 |
| 1979年 | 28267篇 |
| 1978年 | 27484篇 |
| 1977年 | 26231篇 |
| 1976年 | 23308篇 |
| 1975年 | 21306篇 |
| 1974年 | 20027篇 |
| 1973年 | 19117篇 |
排序方式： 共有10000条查询结果，搜索用时 93 毫秒
971.
Yinong Young-Xu Julia Thornton Snider Robertus van Aalst Salaheddin M. Mahmud Edward W. Thommes Jason K.H. Lee David P. Greenberg Ayman Chit 《Vaccine》2019,37(11):1484-1490
Background
Observational studies of the relative effectiveness of influenza vaccines are essential for public health decision making. Their estimates, however, are subject to bias due to unmeasured confounders. Instrumental variable (IV) methods can control for observed and unobserved confounders.Methods
We used linked electronic medical record databases in the Veterans Health Administration (VHA) as well as Medicare administrative files to examine the relative vaccine effectiveness (rVE) of high-dose influenza vaccine (HD) versus standard-dose influenza vaccines (SD) in preventing hospitalizations among VHA-enrolled Veterans ≥65?years of age during 5 influenza seasons (2010–2011 through 2014–2015). Using multivariable IV Poisson regression modeling to address unmeasured confounding and bias, we analyzed the data by each season and through longitudinal analysis of all five seasons.Findings
We included 3,638,924 person–influenza seasons of observation where 158,636 (4%) were among HD vaccine recipients and 3,480,288 (96%) were among SD vaccine recipients. Of the 1,728,562 Veterans, 1,702,824 (98.5%) were male and 1,299,412 (75%) were non-Hispanic white. Based on the longitudinal analysis of all five seasons, the IV-adjusted rVE estimate of HD vs. SD was 10% (95% CI, 8–12%) against all-cause hospitalization; 18% (95% CI, 15–21%) against cardiorespiratory-associated hospitalization; and 14% (95% CI, 6–22%) against influenza/pneumonia-associated hospitalization. The findings by season were similar.Interpretation
Our analysis of VHA clinical data collected from approximately 1.7 million Veterans 65?years and older during five seasons demonstrates that high-dose influenza vaccine is more effective than standard-dose influenza vaccines in preventing influenza- or pneumonia-associated hospitalizations, cardiorespiratory hospitalizations, and all-cause hospitalizations. 相似文献972.
Katherine M. Duszynski Nicole L. Pratt John W. Lynch Jesia G. Berry Michael S. Gold 《Vaccine》2019,37(2):280-288
Objective
To determine whether differences in combination DTaP vaccine types at 2, 4 and 6?months of age were associated with mortality (all-cause or non-specific), within 30?days of vaccination.Design
Observational nationwide cohort study.Setting
Linked population data from the Australian Childhood Immunisation Register and National Death Index.Participants
Australian infants administered a combination trivalent, quadrivalent or hexavalent DTaP vaccine (DTaP types) between January 1999 and December 2010 at 2, 4 and 6?months as part of the primary vaccination series. The study population included 2.9, 2.6, & 2.3?million children in the 2, 4 and 6?month vaccine cohorts, respectively.Main outcome measures
Infants were evaluated for the primary outcome of all-cause mortality within 30?days. A secondary outcome was non-specific mortality (unknown cause of death) within 30?days of vaccination. Non-specific mortality was defined as underlying or other cause of death codes, R95 ‘Sudden infant death syndrome’, R96 ‘Other sudden death, cause unknown’, R98 ‘Unattended death’, R99 ‘Other ill-defined and unspecified cause of mortality’ or where no cause of death was recorded.Results
The rate of 30?day all-cause mortality was low and declined from 127.4 to 59.3 deaths per 100,000 person-years between 2 and 6?month cohorts. When compared with trivalent DTaP vaccines, no elevated risk in all-cause or non-specific mortality was seen with any quadrivalent or hexavalent DTaP vaccines, for any cohort.Conclusion
Use of routine DTaP combination vaccines with differing disease antigens administered during the first six months of life is not associated with infant mortality. 相似文献973.
974.
Stress Testing Versus CT Angiography in Patients With Diabetes and Suspected Coronary Artery Disease
Abhinav Sharma Adrian Coles Nishant K. Sekaran Neha J. Pagidipati Michael T. Lu Daniel B. Mark Kerry L. Lee Hussein R. Al-Khalidi Udo Hoffmann Pamela S. Douglas 《Journal of the American College of Cardiology》2019,73(8):893-902
Background
The optimal noninvasive test (NIT) for patients with diabetes and stable symptoms of coronary artery disease (CAD) is unknown.Objectives
The purpose of this study was to assess whether a diagnostic strategy based on coronary computed tomographic angiography (CTA) is superior to functional stress testing in reducing adverse cardiovascular (CV) outcomes (CV death or myocardial infarction [MI]) among symptomatic patients with diabetes.Methods
PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) was a randomized trial evaluating an initial strategy of CTA versus functional testing in stable outpatients with symptoms suggestive of CAD. The study compared CV outcomes in patients with diabetes (n = 1,908 [21%]) and without diabetes (n = 7,058 [79%]) based on their randomization to CTA or functional testing.Results
Patients with diabetes (vs. without) were similar in age (median 61 years vs. 60 years) and sex (female 54% vs. 52%) but had a greater burden of CV comorbidities. Patients with diabetes who underwent CTA had a lower risk of CV death/MI compared with functional stress testing (CTA: 1.1% [10 of 936] vs. stress testing: 2.6% [25 of 972]; adjusted hazard ratio: 0.38; 95% confidence interval: 0.18 to 0.79; p = 0.01). There was no significant difference in nondiabetic patients (CTA: 1.4% [50 of 3,564] vs. stress testing: 1.3% [45 of 3,494]; adjusted hazard ratio: 1.03; 95% confidence interval: 0.69 to 1.54; p = 0.887; interaction term for diabetes p value = 0.02).Conclusions
In diabetic patients presenting with stable chest pain, a CTA strategy resulted in fewer adverse CV outcomes than a functional testing strategy. CTA may be considered as the initial diagnostic strategy in this subgroup. (PROspective Multicenter Imaging Study for Evaluation of Chest Pain [PROMISE]; NCT01174550) 相似文献975.
O’Beirne Sarah L. Chazen J. Levi Cornman-Homonoff Joshua Carey Bridget T. Gelbman Brian D. 《Lung》2019,197(6):727-733
Lung - Diaphragmatic paralysis (DP) is an important cause of dyspnea with many underlying etiologies; however, frequently no cause is identified despite extensive investigation. We hypothesized... 相似文献
976.
977.
北京市神经外科研究所是国内培养神经外科人才的高端基地之一。近 10 年来，研究所培养了近 200名研究生，其中包括博士研究生 78 人，硕士研究生 120 人。通过对近 10 年来研究所硕士及博士研究生毕业就业情况梳理，分析三甲医院毕业生就业率、京内就业率、京外就业率及总体就业率情况，探讨提升研究所研究生培养质量的途径，以达到提高研究生核心竞争力的目的，以期对神经外科高层次的医学人才培养提供有益建议，为各级医疗卫生机构提供高层次的神经外科高端人才。 相似文献
978.
979.
980.
Tarandovskiy Ivan D. Rajabi Ali A. Karnaukhova Elena Buehler Paul W. 《Journal of thrombosis and thrombolysis》2019,48(1):81-87
Journal of Thrombosis and Thrombolysis - C1-inhibitor (C1INH) was shown to enhance thrombin generation (TG) in the presence of thrombomodulin (TM) by reducing production of activated protein C.... 相似文献