全文获取类型
收费全文 | 9470篇 |
免费 | 654篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 66篇 |
儿科学 | 148篇 |
妇产科学 | 222篇 |
基础医学 | 1279篇 |
口腔科学 | 229篇 |
临床医学 | 799篇 |
内科学 | 2442篇 |
皮肤病学 | 102篇 |
神经病学 | 1073篇 |
特种医学 | 323篇 |
外科学 | 1030篇 |
综合类 | 124篇 |
一般理论 | 9篇 |
预防医学 | 826篇 |
眼科学 | 304篇 |
药学 | 687篇 |
1篇 | |
中国医学 | 24篇 |
肿瘤学 | 468篇 |
出版年
2023年 | 62篇 |
2021年 | 174篇 |
2020年 | 119篇 |
2019年 | 165篇 |
2018年 | 194篇 |
2017年 | 117篇 |
2016年 | 163篇 |
2015年 | 173篇 |
2014年 | 220篇 |
2013年 | 398篇 |
2012年 | 502篇 |
2011年 | 560篇 |
2010年 | 330篇 |
2009年 | 327篇 |
2008年 | 499篇 |
2007年 | 536篇 |
2006年 | 509篇 |
2005年 | 577篇 |
2004年 | 468篇 |
2003年 | 441篇 |
2002年 | 446篇 |
2001年 | 224篇 |
2000年 | 214篇 |
1999年 | 193篇 |
1998年 | 115篇 |
1997年 | 81篇 |
1996年 | 64篇 |
1995年 | 73篇 |
1994年 | 59篇 |
1993年 | 63篇 |
1992年 | 142篇 |
1991年 | 125篇 |
1990年 | 107篇 |
1989年 | 99篇 |
1988年 | 87篇 |
1987年 | 78篇 |
1986年 | 80篇 |
1985年 | 83篇 |
1984年 | 62篇 |
1983年 | 68篇 |
1982年 | 61篇 |
1981年 | 68篇 |
1980年 | 52篇 |
1979年 | 60篇 |
1978年 | 61篇 |
1977年 | 49篇 |
1975年 | 52篇 |
1974年 | 47篇 |
1973年 | 49篇 |
1970年 | 45篇 |
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
1.
Chu-Chih Chen Yin-Han Wang Wei J. Chen Chao A. Hsiung Yue-Liang Leon Guo Shu-Li Julie Wang 《International journal of hygiene and environmental health》2019,222(6):971-980
IntroductionPrenatal exposure to di(2-ethylhexyl) phthalate (DEHP) has been reported to be associated with adverse effects on neurodevelopment that yield behavior syndromes in young children with an estimated median exposure lower than the currently recommended tolerable daily intake (TDI) and reference dose (RfD).ObjectivesOur aim was to derive the benchmark dose for prenatal exposure to DEHP for the neurodevelopmental health in children.MethodsA total of 122 mother-child pairs from the Taiwan Maternal and Infant Cohort Study were analyzed for the dose-response relationship between maternal exposure to DEHP and children's behavioral syndromes evaluated at 8 years (n = 122, 2009), 11 years (n = 96, 2012), and 14 years (n = 78, 2015) of age. We employed a multivariate regression model to assess the statistical associations between the estimated maternal average daily intake of DEHP and child's individual CBCL scores for boys and girls at each separate age, followed by a mixed model for all the children across three ages accounting for individual variations. We then employed structural equation models by combining the children's specific behavioral problem scores at different ages and obtained a simulated overall latent score in relation to maternal exposure. Based on the established dose-response relationship, we derived the benchmark dose (BMD) and the lower limit (BMDL).ResultsAssociations of maternal DEHP exposure (median 4.54) with the Child Behavior Checklist (CBCL) scores were all significant, except for somatic complaints, adjusting for child's age, gender, IQ, and family income. The BMDL, given a benchmark response of 0.10 (0.05) and a background response of 0.05, was 6.01 (2.16) for an integrated CBCL score.ConclusionsThe current TDI (RfD) of 50 (20) for DEHP might not protect pregnant women for their children from behavioral problems. There remains the lack of comparable toxicological data. Further investigations are needed. 相似文献
2.
3.
Misung Han Baolian Yang Brice Fernandez Marisa Lafontaine Paula Alcaide‐Leon Angela Jakary Brian L. Burns Melanie A. Morrison Javier E. Villanueva‐Meyer Susan M. Chang Suchandrima Banerjee Janine M. Lupo 《NMR in biomedicine》2021,34(1)
Although combined spin‐ and gradient‐echo (SAGE) dynamic susceptibility‐contrast (DSC) MRI can provide perfusion quantification that is sensitive to both macrovessels and microvessels while correcting for T1‐shortening effects, spatial coverage is often limited in order to maintain a high temporal resolution for DSC quantification. In this work, we combined a SAGE echo‐planar imaging (EPI) sequence with simultaneous multi‐slice (SMS) excitation and blipped controlled aliasing in parallel imaging (blipped CAIPI) at 3 T to achieve both high temporal resolution and whole brain coverage. Two protocols using this sequence with multi‐band (MB) acceleration factors of 2 and 3 were evaluated in 20 patients with treated gliomas to determine the optimal scan parameters for clinical use. ΔR2*(t) and ΔR2(t) curves were derived to calculate dynamic signal‐to‐noise ratio (dSNR), ΔR2*‐ and ΔR2‐based relative cerebral blood volume (rCBV), and mean vessel diameter (mVD) for each voxel. The resulting SAGE DSC images acquired using MB acceleration of 3 versus 2 appeared visually similar in terms of image distortion and contrast. The difference in the mean dSNR from normal‐appearing white matter (NAWM) and that in the mean dSNR between NAWM and normal‐appearing gray matter were not statistically significant between the two protocols. ΔR2*‐ and ΔR2‐rCBV maps and mVD maps provided unique contrast and spatial heterogeneity within tumors. 相似文献
4.
5.
Angela R. Kamer Ronald G. Craig Richard Niederman Juan Fortea Mony J. de Leon 《Periodontology 2000》2020,83(1):242-271
Approximately 47 million people worldwide have been diagnosed with dementia, 60%-80% of whom have dementia of the Alzheimer’s disease type. Unfortunately, there is no cure in sight. Defining modifiable risk factors for Alzheimer’s disease may have a significant impact on its prevalence. An increasing body of evidence suggests that chronic inflammation and microbial dysbiosis are risk factors for Alzheimer’s disease. Periodontal disease is a chronic inflammatory disease that develops in response to response to microbial dysbiosis. Many studies have shown an association between periodontal disease and Alzheimer’s disease. The intent of this paper was to review the existing literature and determine, using the Bradford Hill criteria, whether periodontal disease is causally related to Alzheimer’s disease. 相似文献
6.
7.
8.
9.
10.
Pharmaceutical Research - To develop a physiologically based pharmacokinetic model in adults and children for clobazam, its active metabolite norclobazam and stiripentol and to account for... 相似文献