全文获取类型
收费全文 | 57904篇 |
免费 | 5100篇 |
国内免费 | 197篇 |
专业分类
耳鼻咽喉 | 526篇 |
儿科学 | 1921篇 |
妇产科学 | 1538篇 |
基础医学 | 8604篇 |
口腔科学 | 833篇 |
临床医学 | 8360篇 |
内科学 | 11115篇 |
皮肤病学 | 1255篇 |
神经病学 | 6287篇 |
特种医学 | 1347篇 |
外国民族医学 | 4篇 |
外科学 | 5441篇 |
综合类 | 478篇 |
现状与发展 | 1篇 |
一般理论 | 38篇 |
预防医学 | 6066篇 |
眼科学 | 892篇 |
药学 | 3789篇 |
中国医学 | 60篇 |
肿瘤学 | 4646篇 |
出版年
2023年 | 517篇 |
2022年 | 792篇 |
2021年 | 1613篇 |
2020年 | 1172篇 |
2019年 | 1788篇 |
2018年 | 2047篇 |
2017年 | 1600篇 |
2016年 | 1722篇 |
2015年 | 1810篇 |
2014年 | 2394篇 |
2013年 | 3168篇 |
2012年 | 4579篇 |
2011年 | 4572篇 |
2010年 | 2632篇 |
2009年 | 2378篇 |
2008年 | 3878篇 |
2007年 | 3937篇 |
2006年 | 3587篇 |
2005年 | 3578篇 |
2004年 | 3264篇 |
2003年 | 2994篇 |
2002年 | 2795篇 |
2001年 | 450篇 |
2000年 | 332篇 |
1999年 | 498篇 |
1998年 | 623篇 |
1997年 | 503篇 |
1996年 | 376篇 |
1995年 | 378篇 |
1994年 | 315篇 |
1993年 | 283篇 |
1992年 | 201篇 |
1991年 | 194篇 |
1990年 | 173篇 |
1989年 | 169篇 |
1988年 | 143篇 |
1987年 | 111篇 |
1986年 | 121篇 |
1985年 | 106篇 |
1984年 | 132篇 |
1983年 | 113篇 |
1982年 | 127篇 |
1981年 | 134篇 |
1980年 | 107篇 |
1979年 | 59篇 |
1978年 | 65篇 |
1977年 | 79篇 |
1976年 | 79篇 |
1975年 | 56篇 |
1974年 | 62篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
Cassandra R. OLenick Amir Baniassadi Ryan Michael Andrew Monaghan Jennifer Boehnert Xiao Yu Mary H. Hayden Christine Wiedinmyer Kai Zhang Peter J. Crank Jannik Heusinger Paige Hoel David J. Sailor Olga V. Wilhelmi 《Environmental health perspectives》2020,128(12)
Background: Despite the substantial role indoor exposure has played in heat wave–related mortality, few epidemiological studies have examined the health effects of exposure to indoor heat. As a result, knowledge gaps regarding indoor heat–health thresholds, vulnerability, and adaptive capacity persist.Objective: We evaluated the role of indoor heat exposure on mortality and morbidity among the elderly ( of age) in Houston, Texas.Methods: Mortality and emergency hospital admission data were obtained through the Texas Department of State Health Services. Summer indoor heat exposure was modeled at the U.S. Census block group (CBG) level using building energy models, outdoor weather data, and building characteristic data. Indoor heat–health associations were examined using time-stratified case-crossover models, controlling for temporal trends and meteorology, and matching on CBG of residence, year, month, and weekday of the adverse health event. Separate models were fitted for three indoor exposure metrics, for individual lag days 0–6, and for 3-d moving averages (lag 0–2). Effect measure modification was explored via stratification on individual- and area-level vulnerability factors.Results: We estimated positive associations between short-term changes in indoor heat exposure and cause-specific mortality and morbidity [e.g., circulatory deaths, (95% CI: 1.03, 1.30)]. Associations were generally positive for earlier lag periods and weaker across later lag periods. Stratified analyses suggest stronger associations between indoor heat and emergency hospital admissions among African Americans compared with Whites.Discussion: Findings suggest excess mortality among certain elderly populations in Houston who are likely exposed to high indoor heat. We developed a novel methodology to estimate indoor heat exposure that can be adapted to other U.S. locations. In locations with high air conditioning prevalence, simplified modeling approaches may adequately account for indoor heat exposure in vulnerable neighborhoods. Accounting for indoor heat exposure may improve the estimation of the total impact of heat on health. https://doi.org/10.1289/EHP6340 相似文献
995.
996.
Jan Kucera Jana Ruda-Kucerova Filip Zlamal Daniela Kuruczova Zuzana Babinska Josef Tomandl Marie Tomandlova Julie Bienertova-Vasku 《Pharmacological reports : PR》2019,71(4):669-675
BackgroundNeurotrophins, especially brain-derived neurotrophic factor (BDNF) have gained significant therapeutic interest particularly in neurologic and psychiatric disorders and they have been found in human breast milk of mothers who suffered from adverse outcomes in pregnancy. This study tested the hypothesis that oral administration of BDNF/GDNF (glial cell line-derived neurotrophic factor) can exert a biological effect in a rat model of severe neuropathology induced by olfactory bulbectomy (OBX), which exhibits dysregulation of BDNF signaling and impaired blood-brain barrier.MethodsAdult male albino Sprague-Dawley rats underwent the OBX surgery and separate groups of OBX and sham-operated controls received one oral dose of vehicle, BDNF (0.005 mg/kg), GDNF (0.03 mg/kg) or their combination. One week after neurotrophin dosing the rats were sacrificed and BDNF level was assessed by ELISA in the blood serum and cerebrospinal fluid.ResultsA significant decrease of serum BDNF level was found in the OBX model. This alteration was normalized by all types of treatment BDNF, GDNF, or their combination. No influence of sham surgery or treatment was observed in the control rats. BDNF levels in cerebrospinal fluid were below detection limit.ConclusionThis study indicates that oral administration of neurotrophins is able to exert a biological effect in the OBX model. There is a number of potential mechanisms, which remain to be elucidated. 相似文献
997.
In psychiatry, clinicians use criteria sets from the Diagnostic and Statistical Manual of Mental Disorders to diagnose mental disorders. Most criteria sets have several symptom domains, and in order to be diagnosed, an individual must meet the minimum number of symptoms required by each domain. Some efforts are now focused on adding biomarkers to these symptom domains to facilitate the detection of and highlight the neurobiological basis of psychiatric disorders. Thus, a new criteria set may consist of both clinical symptom counts in several domains and continuous biomarkers. In this paper, we propose a method to integrate classification rules from multiple data sources to estimate an optimal criteria set. Each domain-specific rule can be counts of symptoms, a linear function of symptoms, or even nonparametric. The overall classification rule is the intersection of these domain-specific rules. Based on examining the expected population loss function, we propose two iterative algorithms using either support vector machines or logistic regression to fit intersection rules consistent with the Diagnostic and Statistical Manual of Mental Disorders. In simulation studies, these proposed methods are comparable with the true decision rule. The methods are applied to the motivating study to construct a criteria set for complicated grief. The developed criteria set shows a substantial improvement in sensitivity and specificity compared to the current standards on an independent validation study. 相似文献
998.
999.
1000.
Leila H. Shayegan BA MD Candidate Maria C. Garzon MD Kimberly D. Morel MD Rachel Borlack MD Patricia M. Vuguin MD Kara G. Margolis MD Yesim Y. Demirdag MD Elaine M. Pereira MD Christine T. Lauren MD MHA 《Pediatric dermatology》2020,37(4):695-697
We report a case of a newly recognized primary immunodeficiency due to biallelic mutations in CARMIL2 manifesting as an actinic prurigo-like photodermatitis, allergic diathesis and recurrent infections in a child. We present this case to highlight a rare phenotype seen in this T-cell immunodeficiency and provide an overview of other dermatologic manifestations among published reports of this condition. 相似文献