全文获取类型
| 收费全文 | 1425972篇 |
| 免费 | 114662篇 |
| 国内免费 | 3368篇 |
专业分类
| 耳鼻咽喉 | 18476篇 |
| 儿科学 | 47149篇 |
| 妇产科学 | 41518篇 |
| 基础医学 | 202677篇 |
| 口腔科学 | 37899篇 |
| 临床医学 | 127758篇 |
| 内科学 | 287169篇 |
| 皮肤病学 | 33618篇 |
| 神经病学 | 118558篇 |
| 特种医学 | 54066篇 |
| 外国民族医学 | 469篇 |
| 外科学 | 212077篇 |
| 综合类 | 32872篇 |
| 现状与发展 | 3篇 |
| 一般理论 | 552篇 |
| 预防医学 | 112350篇 |
| 眼科学 | 31727篇 |
| 药学 | 99465篇 |
| 2篇 | |
| 中国医学 | 3382篇 |
| 肿瘤学 | 82215篇 |
出版年
| 2021年 | 11584篇 |
| 2019年 | 12278篇 |
| 2018年 | 17295篇 |
| 2017年 | 13193篇 |
| 2016年 | 14778篇 |
| 2015年 | 16575篇 |
| 2014年 | 23296篇 |
| 2013年 | 34365篇 |
| 2012年 | 46698篇 |
| 2011年 | 49264篇 |
| 2010年 | 28851篇 |
| 2009年 | 27611篇 |
| 2008年 | 45286篇 |
| 2007年 | 47866篇 |
| 2006年 | 48218篇 |
| 2005年 | 46610篇 |
| 2004年 | 44441篇 |
| 2003年 | 42311篇 |
| 2002年 | 40647篇 |
| 2001年 | 73058篇 |
| 2000年 | 74566篇 |
| 1999年 | 61602篇 |
| 1998年 | 17079篇 |
| 1997年 | 15498篇 |
| 1996年 | 15612篇 |
| 1995年 | 14833篇 |
| 1994年 | 13432篇 |
| 1993年 | 12618篇 |
| 1992年 | 45860篇 |
| 1991年 | 43492篇 |
| 1990年 | 41500篇 |
| 1989年 | 39566篇 |
| 1988年 | 36181篇 |
| 1987年 | 35359篇 |
| 1986年 | 32871篇 |
| 1985年 | 31290篇 |
| 1984年 | 23835篇 |
| 1983年 | 20029篇 |
| 1982年 | 12217篇 |
| 1981年 | 10792篇 |
| 1979年 | 20703篇 |
| 1978年 | 14581篇 |
| 1977年 | 12092篇 |
| 1976年 | 11369篇 |
| 1975年 | 11625篇 |
| 1974年 | 13996篇 |
| 1973年 | 13535篇 |
| 1972年 | 12635篇 |
| 1971年 | 11473篇 |
| 1970年 | 10913篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
61.
62.
Hanna Lee Mary K. Tan Andrew T. Yan Paul Angaran Paul Dorian Claudia Bucci Jean C. Gregoire Alan D. Bell Martin S. Green Peter L. Gross Allan Skanes Charles R. Kerr L. Brent Mitchell Jafna L. Cox Vidal Essebag Brett Heilbron Krishnan Ramanathan Carl Fournier Shaun G. Goodman 《The Canadian journal of cardiology》2019,35(2):160-168
Background
Physicians treating nonvalvular atrial fibrillation (AF) assess stroke and bleeding risks when deciding on anticoagulation. The agreement between empirical and physician-estimated risks is unclear. Furthermore, the association between patient and physician sex and anticoagulation decision-making is uncertain.Methods
We pooled data from 2 national primary care physician chart audit databases of patients with AF (Facilitating Review and Education to Optimize Stroke Prevention in Atrial Fibrillation and Coordinated National Network to Engage Physicians in the Care and Treatment of Patients with Atrial Fibrillation Chart Audit) with a combined 1035 physicians (133 female, 902 male) and 10,927 patients (4567 female and 6360 male).Results
Male physicians underestimated stroke risk in female patients and overestimated risk in male patients. Female physicians estimated stroke risk well in female patients but underestimated the risk in male patients. Risk of bleeding was underestimated in all. Despite differences in risk assessment by physician and patient sex, > 90% of patients received anticoagulation across all subgroups. There was modest agreement between physician estimated and calculated (ie, CHADS2 score) stroke risk: Kappa scores were 0.41 (0.35-0.47) for female physicians and 0.34 (0.32-0.36) for male physicians.Conclusions
Our study is the first to examine the association between patient and physician sex influences and stroke and bleeding risk estimation in AF. Although there were differences in agreement between physician estimated stroke risk and calculated CHADS2 scores, these differences were small and unlikely to affect clinical practice; further, despite any perceived differences in the accuracy of risk assessment by sex, most patients received anticoagulation. 相似文献63.
64.
65.
K.-C. Sung D.-C. Seo S.-J. Lee M.-Y. Lee S.H. Wild C.D. Byrne 《Nutrition, metabolism, and cardiovascular diseases : NMCD》2019,29(5):489-495
Background and aims
It is not known whether non alcoholic fatty liver disease (NAFLD) is a risk factor for diabetes in non obese, non centrally-obese subjects. Our aim was to investigate relationships between fatty liver, insulin resistance and a biomarker score for liver fibrosis with incident diabetes at follow up, in subjects who were neither obese nor centrally-obese.Methods and results
As many as 70,303 subjects with a body mass index (BMI) < 25 kg/m2 and without diabetes were followed up for a maximum of 7.9 years. At baseline, fatty liver was identified by liver ultrasound, insulin resistance (IR) by homeostatic model assessment of insulin resistance (HOMA-IR) ≥2.0, and central obesity by waist circumference (waist circumference ≥90 cm (men) and ≥85 cm (women). The Fibrosis-4 (FIB-4 score) was used to estimate extent of liver fibrosis. Cox proportional hazards models adjusted for confounders were used to estimate hazard ratios (aHRs) for incident diabetes. As many as 852 incident cases of diabetes occurred during follow up (median [IQR] 3.71 [2.03] years). Mean ± SD BMI was 22.8 ± 1.8 and 21.7 ± 2.0 kg/m2 in subjects with and without diabetes at follow up. In subjects without central obesity and with fatty liver, aHRs (95% CI) for incident diabetes at follow up were 2.17 (1.56, 3.03) for men, and 2.86 (1.50,5.46) for women. Similar aHRs for incident diabetes occurred with fatty liver, IR and the highest quartile of FIB-4 combined, in men; and there was a non significant trend toward increased risk in women.Conclusions
In normal weight, non-centrally obese subjects NAFLD is an independent risk factor for incident diabetes. 相似文献66.
67.
68.
69.
Maggie L. Westfal David C. Chang Cassandra M. Kelleher 《Journal of pediatric surgery》2019,54(1):140-144
Purpose
The purpose of this study was to evaluate trends in demographics and outcomes of pediatric breast cancer in a United States population-based cohort.Methods
The Surveillance, Epidemiology, and End Results (SEER) database was utilized to identify all pediatric patients with malignant breast tumors between 1973 and 2014. Analysis was performed using Stata Statistical Software version 13.1. Associations between categorical variables were made using X2 test. Log-rank test was used for univariate survival analysis. Kaplan–Meier analysis investigated five-year survival rates across several variables. Adjusted analysis was performed using a Cox Proportional-Hazards regression.Results
134 patients with breast malignancies were identified. Carcinoma was the most prevalent histology (48.5%), followed by fibroepithelial tumors (FETs) (35.1%), and sarcoma (14.2%). FETs were twice as common in black compared to nonblack patients (56.3% vs. 29.0%, p?<?0.01). Analyzing histology by stage revealed that 100% of FETs were early stage disease (p?<?0.0001). 46.7% of the tumors tested were ER/PR negative, more than twice as many compared to the published adult estimate of 20.0%. Unadjusted survival analysis revealed worse survival for patients with adenocarcinoma/sarcomas, advanced stage, and high grade disease, without a survival difference between races.Conclusion
Breast cancer remains a rare malignancy among pediatric patients. Although black patients were found to have more noncarcinomatous tumors with less advanced disease, this did not confer a survival advantage.Type of study
Retrospective cohort study.Level of evidence
Level III. 相似文献70.