全文获取类型
收费全文 | 4112篇 |
免费 | 507篇 |
国内免费 | 180篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 56篇 |
妇产科学 | 25篇 |
基础医学 | 381篇 |
口腔科学 | 93篇 |
临床医学 | 675篇 |
内科学 | 377篇 |
皮肤病学 | 17篇 |
神经病学 | 320篇 |
特种医学 | 94篇 |
外国民族医学 | 1篇 |
外科学 | 138篇 |
综合类 | 453篇 |
预防医学 | 778篇 |
眼科学 | 30篇 |
药学 | 599篇 |
1篇 | |
中国医学 | 617篇 |
肿瘤学 | 135篇 |
出版年
2024年 | 7篇 |
2023年 | 93篇 |
2022年 | 113篇 |
2021年 | 234篇 |
2020年 | 188篇 |
2019年 | 188篇 |
2018年 | 193篇 |
2017年 | 210篇 |
2016年 | 214篇 |
2015年 | 230篇 |
2014年 | 291篇 |
2013年 | 388篇 |
2012年 | 289篇 |
2011年 | 243篇 |
2010年 | 171篇 |
2009年 | 169篇 |
2008年 | 192篇 |
2007年 | 156篇 |
2006年 | 171篇 |
2005年 | 135篇 |
2004年 | 129篇 |
2003年 | 95篇 |
2002年 | 86篇 |
2001年 | 77篇 |
2000年 | 74篇 |
1999年 | 56篇 |
1998年 | 56篇 |
1997年 | 45篇 |
1996年 | 38篇 |
1995年 | 33篇 |
1994年 | 36篇 |
1993年 | 25篇 |
1992年 | 21篇 |
1991年 | 34篇 |
1990年 | 9篇 |
1989年 | 10篇 |
1988年 | 12篇 |
1987年 | 12篇 |
1986年 | 5篇 |
1985年 | 11篇 |
1984年 | 11篇 |
1983年 | 11篇 |
1982年 | 8篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1971年 | 2篇 |
排序方式: 共有4799条查询结果,搜索用时 609 毫秒
1.
In clinical and epidemiological studies, there is a growing interest in studying the heterogeneity among patients based on longitudinal characteristics to identify subtypes of the study population. Compared to clustering a single longitudinal marker, simultaneously clustering multiple longitudinal markers allow additional information to be incorporated into the clustering process, which reveals co-existing longitudinal patterns and generates deeper biological insight. In the current study, we propose a Bayesian consensus clustering (BCC) model for multivariate longitudinal data. Instead of arriving at a single overall clustering, the proposed model allows each marker to follow marker-specific local clustering and these local clusterings are aggregated to find a global (consensus) clustering. To estimate the posterior distribution of model parameters, a Gibbs sampling algorithm is proposed. We apply our proposed model to the primary biliary cirrhosis study to identify patient subtypes that may be associated with their prognosis. We also perform simulation studies to compare the clustering performance between the proposed model and existing models under several scenarios. The results demonstrate that the proposed BCC model serves as a useful tool for clustering multivariate longitudinal data. 相似文献
2.
3.
4.
Julia Thornton Snider Jesse Sussell Mahlet Gizaw Tebeka Alicia Gonzalez Joshua T. Cohen Peter Neumann 《Value in health》2019,22(3):332-339
Background
Payers frequently rely on budget impact model (BIM) results to help determine drug coverage policy and its effect on their bottom line. It is unclear whether BIMs typically overestimate or underestimate real-world budget impact.Objective
We examined how different modeling assumptions influenced the results of 6 BIMs from the Institute for Clinical and Economic Review (ICER).Study Design
Retrospective analysis of pharmaceutical sales data.Methods
From ICER reports issued before 2016, we collected estimates of 3 BIM outputs: aggregate therapy cost (ie, cost to treat the patient population with a particular therapy), therapy uptake, and price. We compared these against real-world estimates that we generated using drug sales data. We considered 2 classes of BIM estimates: those forecasting future uptake of new agents, which assumed “unmanaged uptake,” and those describing the contemporaneous market state (ie, estimates of current, managed uptake and budget impact for compounds already on the market).Results
Differences between ICER's estimates and our own were largest for forecasted studies. Here, ICER's uptake estimates exceeded real-world estimates by factors ranging from 7.4 (sacubitril/valsartan) to 54 (hepatitis C treatments). The “unmanaged uptake” assumption (removed from ICER's approach in 2017) yields large deviations between BIM estimates and real-world consumption. Nevertheless, in some cases, ICER's BIMs that relied on current market estimates also deviated substantially from real-world sales data.Conclusions
This study highlights challenges with forecasting budget impact. In particular, assumptions about uptake and data source selection can greatly influence the accuracy of results. 相似文献5.
摘要:目的对尿液 10项肾损伤标志物检测试剂进行性能评价,并评估其临床适用性。方法对北京利德曼公司尿液a1 微球蛋白(u-a|MG)、总蛋白(u-TP)、免疫球蛋白G(u-IgG) 、微量清蛋白(u-Alb)、中性粒细胞明胶酶相关脂质运载蛋白(u-NGAL)、半胱氨酸蛋白酶抑制剂C(u-CysC).视黄醇结合蛋白(u-RBP)、β2微球蛋白(u-β2MG)、N-乙酰-β-D-氨基葡萄糖苷酶(u-NAG).、转铁蛋白(u-Trf)检测试剂盒进行性能评价。正确度和精密度验证参考美国临床和实验室标准协会(CLSI)EP15-A3,验证物质采用ERM-DA470k、ERM-DA471、B2M-NIBSC等参考物质及纯度物质;线性验证参考CLSI EP06;抗干扰能力参考CISI EP07;不同检测系统间比对参考CISI EP09。结果正确度方面,10 项标志物检测试剂测定标准物质在低值、中值、高值的偏倚分别为-2.69% ~4.67%、-3.60% ~3.33% .-2.38% ~3.02%;不精密度方面,重复性以不精密度表示,在低值和高值处分别为1.90%~5.43%、0.63% ~2.42%,室内不精密度为2.27%~5.63%、1.09%~3.41%,均满足临床要求;10项尿液标志物线性范围在0.06~4.40 mg/L至21.83~2 146.77 mg/L之间。抗干扰方面,u-1 MG、u-Alb、u-β2MG、u-Trf 、u-CysC、u-NAG分别在血红蛋白终浓度≤8 g/L、≤8 g/L、≤4 g/L、≤4 g/L、≤2g/L、≤1 g/L时,未受到明显干扰(百分偏差≤+ 10%) ,而u-TP、u-IgG、
u-RBP、u-NGAL在血红蛋白终浓度≥0.125 g/L时即受干扰。不同检测系统间偏差超出临床允许范围。结论尿液 10项肾损伤标志物的正确度、精密度、线性范围和抗血红蛋白干扰能力满足临床需要,不同检测系统间标志物测量结果可比性欠佳。 相似文献
6.
7.
8.
9.
Patients at Boston's Children's Hospital diagnosed as having cerebral palsy were filmed walking. These films were digitized and translated into measurements associated with leg motion. In this paper we use the gait measurements of 128 such patients to illustrate that the kth nearest neighbour clustering procedure results in a gait typology for patients with cerebral palsy. The procedure identifies four subpopulations from the sample data; the membership of a patient within this typology is mostly determined by the patient's motor control. The developed typology differs from the present diagnostic system which classifies a cerebral palsy patient as either quadriplegic, diaplegic or hemiplegic. 相似文献
10.
R. A. Wolfe F. B. LaPorte A. M. Rodgers E. C. Roys G. Fant A. B. Leichtman 《American journal of transplantation》2007,7(S1):1404-1411
Turndowns of offers of deceased donor kidneys for transplantation can contribute to inefficiencies in the organ distribution system and inequality in access to donated organs. Match run data were obtained for 4967 'good' kidneys placed and transplanted in 2005 after fewer than 50 offers. These kidneys were not recovered from donation after cardiac death or expanded criteria donors, or from donors with a history of substance abuse. On average, these good kidneys were not accepted until after seven offers to candidates and after offers to 2.4 programs. Models for the likelihood of acceptance found several donor and candidate characteristics to be significantly related to acceptance rates (p < 0.05). After accounting for these variables, there remained 2- to 3-fold differences among transplant programs in acceptance rates. These models could be used to identify kidney transplant centers with exceptional acceptance practices. Several strategies might be employed to increase acceptance rates for good organs. 相似文献