全文获取类型
收费全文 | 1303360篇 |
免费 | 99871篇 |
国内免费 | 2058篇 |
专业分类
耳鼻咽喉 | 18806篇 |
儿科学 | 44842篇 |
妇产科学 | 35514篇 |
基础医学 | 185360篇 |
口腔科学 | 34028篇 |
临床医学 | 114185篇 |
内科学 | 263300篇 |
皮肤病学 | 28354篇 |
神经病学 | 102535篇 |
特种医学 | 52119篇 |
外国民族医学 | 660篇 |
外科学 | 200609篇 |
综合类 | 27267篇 |
现状与发展 | 1篇 |
一般理论 | 429篇 |
预防医学 | 97502篇 |
眼科学 | 28566篇 |
药学 | 96424篇 |
26篇 | |
中国医学 | 2452篇 |
肿瘤学 | 72310篇 |
出版年
2019年 | 9859篇 |
2018年 | 13997篇 |
2017年 | 10571篇 |
2016年 | 11573篇 |
2015年 | 13153篇 |
2014年 | 18310篇 |
2013年 | 27540篇 |
2012年 | 38094篇 |
2011年 | 40160篇 |
2010年 | 23904篇 |
2009年 | 22841篇 |
2008年 | 38189篇 |
2007年 | 40784篇 |
2006年 | 40915篇 |
2005年 | 39771篇 |
2004年 | 38758篇 |
2003年 | 37446篇 |
2002年 | 36657篇 |
2001年 | 64211篇 |
2000年 | 66667篇 |
1999年 | 56560篇 |
1998年 | 15254篇 |
1997年 | 13844篇 |
1996年 | 14259篇 |
1995年 | 13501篇 |
1994年 | 12813篇 |
1993年 | 11828篇 |
1992年 | 44641篇 |
1991年 | 43533篇 |
1990年 | 42277篇 |
1989年 | 40184篇 |
1988年 | 36967篇 |
1987年 | 36294篇 |
1986年 | 33667篇 |
1985年 | 32345篇 |
1984年 | 24184篇 |
1983年 | 20304篇 |
1982年 | 11759篇 |
1981年 | 10725篇 |
1979年 | 21385篇 |
1978年 | 14856篇 |
1977年 | 12556篇 |
1976年 | 11720篇 |
1975年 | 12651篇 |
1974年 | 14687篇 |
1973年 | 14147篇 |
1972年 | 12968篇 |
1971年 | 11763篇 |
1970年 | 11074篇 |
1969年 | 10045篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
73.
74.
75.
Jason S. Melo Maria Luisa Mittal Danielle Horyniak Steffanie A. Strathdee 《Substance use & misuse》2018,53(9):1558-1570
Background: Dual epidemics of injection drug use and blood-borne disease, characterized as “syndemics,” are present in a range of settings. Behaviors that drive such syndemics are particularly prevalent among mobile drug-using populations, for whom cross-border migration may pose additional risks. Objectives: This narrative review aims to characterize the risk factors for injection drug use initiation associated with migration, employing a risk environment framework and focusing on the San Diego–Tijuana border region as the most dynamic example of these phenomena. Methods: Based on previous literature, we divide migration streams into three classes: intra-urban, internal, and international. We synthesized existing literature on migration and drug use to characterize how mobility and migration drive the initiation of injection drug use, as well as the transmission of hepatitis and HIV, and to delineate how these might be addressed through public health intervention. Results: Population mixing between migrants and receiving communities and the consequent transmission of social norms about injection drug use create risk environments for injection drug use initiation. These risk environments have been characterized as a result of local policy environments, injection drug use norms in receiving communities, migration-related stressors, social dislocation, and infringement on the rights of undocumented migrants. Conclusion: Policies that exacerbate risk environments for migrants may inadvertently contribute to the expansion of epidemics of injection-driven blood-borne disease. Successful interventions that address emerging syndemics in border regions may therefore need to be tailored to migrant populations and distinguish between the vulnerabilities experienced by different migration classes and border settings. 相似文献
76.
Emily E. Burns Laura J. Carter Jason Snape Jane Thomas-Oates 《Journal of toxicology and environmental health. Part B, Critical reviews》2018,21(3):115-141
Pharmaceuticals are ubiquitous in the natural environment with concentrations expected to rise as human population increases. Environmental risk assessments are available for a small portion of pharmaceuticals in use, raising concerns over the potential risks posed by other drugs that have little or no data. With >1900 active pharmaceutical ingredients in use, it would be a major task to test all of the compounds with little or no data. Desk-based prioritization studies provide a potential solution by identifying those substances that are likely to pose the greatest risk to the environment and which, therefore, need to be considered a priority for further study. The aim of this review was to (1) provide an overview of different prioritization exercises performed for pharmaceuticals in the environment and the results obtained; and (2) propose a new holistic risk-based prioritization framework for drugs in the environment. The suggested models to underpin this framework are discussed in terms of validity and applicability. The availability of data required to run the models was assessed and data gaps identified. The implementation of this framework may harmonize pharmaceutical prioritization efforts and ensure that, in the future, experimental resources are focused on molecules, endpoints, and environmental compartments that are biologically relevant. 相似文献
77.
Deverick J Anderson Luke F Chen David J Weber Rebekah W Moehring Sarah S Lewis Patricia F Triplett Michael Blocker Paul Becherer J Conrad Schwab Lauren P Knelson Yuliya Lokhnygina William A Rutalo Hajimori Kanamori Marina F Gergen Daniel J Sexton for the CDC Prevention Epicenters Program 《中华医院感染学杂志》2018,(12)
中文:背景患者入院后可从不当消毒的环境表面获得多药耐药菌和艰难梭菌。本文确定了3种强化的终末消毒(入住同一病房的两名患者之间的消毒)策略,对感染耐甲氧西林金黄色葡萄球菌(MRSA)、耐万古霉素肠球菌(VRE)、艰难梭菌(CD)和多重耐药不动杆菌的影响。方法本文在美国东南部的9家医院开展了一项务实的、集群-随机、交叉研究。凡曾有感染或定植目标细菌感染患者居住过的病房,患者出院后随机采取4种消毒策略中的一种方法进行终末消毒:对照(季胺盐类消毒剂消毒,但凡遇到CD采用含氯消毒剂);UV(季胺盐类+UV-C消毒,但凡遇到CD采用含氯消毒剂+UV-C);含氯消毒剂;含氯消毒剂+UV-C。凡入住目标病房的患者被列为暴露人群。这4种终末消毒方法分别在每家医院连续实施7个月的周期。本文随机设计这几种消毒策略在每家医院内的实施顺序(1:1:1:1)。主要产出的结果是,观察暴露患者中目标细菌的感染的发生或定植情况,以及ITT人群中暴露患者CD感染发生率。本研究ClinicalTrials.gov注册编号:NCT01579370。结果共有31 226名患者暴露,其中21 395(69%)符合标准,包括4 916名对照组,5 178名UV组,5 438名含氯消毒剂组,以及5 863名含氯消毒剂+UV组。在对照组中,22 426个暴露日中有115名患者发生目标细菌的感染(51.3/10000暴露日)。在标准清洁策略的基础上增加UV消毒的暴露患者,其目标细菌感染的发生率明显较低(n=76;33.9/10 000暴露日;RR:0.70,95%CI:0.50~0.988;P=0.036)。含氯消毒剂组(n=101;41.6/10 000暴露日;RR:0.85,95%CI:0.69~1.04;P=0.116),或含氯消毒剂+UV组患者(n=131;45.6/10 000暴露日;RR:0.91,95%CI:0.76~1.09;P=0.303)的目标细菌的感染率,其差异无统计学意义。同样,在含氯消毒剂的基础上增加UV消毒,暴露患者中CD感染率也没有发生改变((n=38 vs 36;30.4 vs 31.6/10 000暴露日;RR:1.0,95%CI:0.57-1.75;P=0.997)。解释污染的医疗机构环境是获得病原微生物的重要来源;强化终末消毒可以降低这一风险。 相似文献
78.
79.
Juan R. Ordoñana Juan F. Sánchez Romera Lucía Colodro-Conde Eduvigis Carrillo Francisca González-Javier Juan J. Madrid-Valero José J. Morosoli-García Francisco Pérez-Riquelme José M. Martínez-Selva 《Gaceta sanitaria / S.E.S.P.A.S》2018,32(1):92-95
Genetically informative designs and, in particular, twin studies, are the most widely used methodology to analyse the relative contribution of genetic and environmental factors to inter-individual variability. These studies basically compare the degree of phenotypical similarity between monozygotic and dizygotic twin pairs. In addition to the traditional estimate of heritability, this kind of registry enables a wide variety of analyses which are unique due to the characteristics of the sample. The Murcia Twin Registry is population-based and focused on the analysis of health-related behaviour. The observed prevalence of health problems is comparable to that of other regional and national reference samples, which guarantees its representativeness. Overall, the characteristics of the Registry facilitate developing various types of research as well as genetically informative designs, and collaboration with different initiatives and consortia. 相似文献
80.