全文获取类型
收费全文 | 29747篇 |
免费 | 2781篇 |
国内免费 | 48篇 |
专业分类
耳鼻咽喉 | 221篇 |
儿科学 | 1045篇 |
妇产科学 | 977篇 |
基础医学 | 4226篇 |
口腔科学 | 630篇 |
临床医学 | 3986篇 |
内科学 | 5473篇 |
皮肤病学 | 390篇 |
神经病学 | 2867篇 |
特种医学 | 756篇 |
外科学 | 3475篇 |
综合类 | 635篇 |
一般理论 | 33篇 |
预防医学 | 3465篇 |
眼科学 | 404篇 |
药学 | 2224篇 |
中国医学 | 40篇 |
肿瘤学 | 1729篇 |
出版年
2022年 | 170篇 |
2021年 | 460篇 |
2020年 | 290篇 |
2019年 | 527篇 |
2018年 | 603篇 |
2017年 | 419篇 |
2016年 | 468篇 |
2015年 | 561篇 |
2014年 | 790篇 |
2013年 | 1181篇 |
2012年 | 1721篇 |
2011年 | 1715篇 |
2010年 | 949篇 |
2009年 | 876篇 |
2008年 | 1505篇 |
2007年 | 1669篇 |
2006年 | 1538篇 |
2005年 | 1476篇 |
2004年 | 1511篇 |
2003年 | 1337篇 |
2002年 | 1264篇 |
2001年 | 761篇 |
2000年 | 732篇 |
1999年 | 683篇 |
1998年 | 335篇 |
1997年 | 308篇 |
1996年 | 274篇 |
1995年 | 278篇 |
1994年 | 254篇 |
1993年 | 230篇 |
1992年 | 551篇 |
1991年 | 530篇 |
1990年 | 462篇 |
1989年 | 546篇 |
1988年 | 452篇 |
1987年 | 408篇 |
1986年 | 455篇 |
1985年 | 365篇 |
1984年 | 320篇 |
1983年 | 335篇 |
1982年 | 193篇 |
1981年 | 184篇 |
1979年 | 253篇 |
1978年 | 194篇 |
1977年 | 164篇 |
1976年 | 168篇 |
1974年 | 156篇 |
1973年 | 184篇 |
1972年 | 154篇 |
1971年 | 165篇 |
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
991.
Jill G. Zwicker Ruth E. Grunau Elysia Adams Vann Chau Rollin Brant Kenneth J. Poskitt Anne Synnes Steven P. Miller 《Pediatric neurology》2013,48(2):123-129.e1
Premature infants are at risk for adverse motor outcomes, including cerebral palsy and developmental coordination disorder. The purpose of this study was to examine the relationship of antenatal, perinatal, and postnatal risk factors for abnormal development of the corticospinal tract, the major voluntary motor pathway, during the neonatal period. In a prospective cohort study, 126 premature neonates (24-32 weeks' gestational age) underwent serial brain imaging near birth and at term-equivalent age. With diffusion tensor tractography, mean diffusivity and fractional anisotropy of the corticospinal tract were measured to reflect microstructural development. Generalized estimating equation models examined associations of risk factors on corticospinal tract development. The perinatal risk factor of greater early illness severity (as measured by the Score for Neonatal Acute Physiology–II [SNAP-II]) was associated with a slower rise in fractional anisotropy of the corticospinal tract (P = 0.02), even after correcting for gestational age at birth and postnatal risk factors (P = 0.009). Consistent with previous findings, neonatal pain adjusted for morphine and postnatal infection were also associated with a slower rise in fractional anisotropy of the corticospinal tract (P = 0.03 and 0.02, respectively). Lessening illness severity in the first hours of life might offer potential to improve motor pathway development in premature newborns. 相似文献
992.
Johnny L. Matson Timothy Dempsey Santino V. LoVullo Jill C. Fodstad Cheryl Knight Jay A. Sevin Brenda Sharp 《Research in developmental disabilities》2013,34(1):573-578
Little research has been conducted on whether deficits in developmental functioning affect the range of core symptoms for autism spectrum disorders (ASD). This study represents a first attempt to determine whether developmental level has an effect on the expression of ASD symptoms in infants and toddlers. Eight hundred and fifty-three infants were evaluated with respect to the nature and extent of their ASD symptoms and developmental functioning. Young children with autism displayed a higher number of symptoms than those with PDD-NOS on all three domains of impairment (social, communication, repetitive behaviors). As expected, children without an ASD evinced far fewer symptoms than both these groups. Developmental level was not found to be a moderator for expression of ASD symptoms for the entire sample, or individual diagnostic groups. Higher developmental level was associated with lower severity of evinced ASD symptoms in the sample. 相似文献
993.
Stewart C. Morrison Jill Ferrari Sally Smillie 《Research in developmental disabilities》2013,34(10):3197-3201
Developmental Coordination Disorder (DCD) is a neurodevelopmental disorder characterised by impaired motor co-ordination and awkward gait. Despite self-reported findings of pes planus and joint hypermobility in children with DCD, there is little objective evidence regarding the clinical management of the foot in children with DCD. The aims of this research were to report clinical findings of foot posture and lower limb hypermobility in children with DCD and to evaluate the impact of foot orthoses on spatio-temporal gait parameters. Children with DCD were recruited into the study. Participants were randomly assigned to an intervention group who received foot orthoses at the start of their rehabilitation programme or to a second group who received foot orthoses at the end of their intervention programme. Foot posture was assessed with the Foot Posture Index and lower limb hypermobility assessed with the Lower Limb Assessment Score. The effect of foot orthoses was evaluated through assessment of spatio-temporal gait characteristics at baseline and post-rehabilitation programme. Fourteen children were recruited (mdn age 7.5 years) with nine children assigned to the group receiving orthoses early (mdn age 8 years) and five children assigned to the post-rehabilitation orthoses group (mdn age 6.5 years). A pes planus foot posture (FPI score = 8) and lower limb hypermobility (LLAS score = 11) were observed. Changes in spatio-temporal gait parameters failed to reach significance (p > .012) following orthotic invention but demonstrated a trend towards a decreased cadence and increased double support duration. Despite non-significant findings this work offers preliminary support for podiatric intervention in the rehabilitation of children with DCD. Further work is required to understand the biomechanics of gait in children with DCD and appreciate the role of podiatry as a component of multidisciplinary care. 相似文献
994.
Chao-Ying Chen Warren D. Lo Jill C. Heathcock 《Research in developmental disabilities》2013,34(3):1011-1017
Upper extremity movements, midline behaviors, fine, and gross motor skills are frequently impaired in hemiparesis and cerebral palsy. We investigated midline toy exploration and fine and gross motor skills in infants at risk for hemiplegic cerebral palsy. Eight infants with neonatal stroke (NS) and thirteen infants with typical development (TD) were assessed from 2 to 7 months of age. The following variables were analyzed: percentage of time in midline and fine and gross motor scores on the Bayley Scales of Infant Development (BSID-III). Infants with neonatal stroke demonstrated poor performance in midline behaviors and fine and gross motor scores on the BSID-III. These results suggest that infants with NS have poor midline behaviors and motor skill development early in infancy. 相似文献
995.
Katerina Zavitsanou Victoria S. Dalton Adam K. Walker Cynthia S. Weickert Luba Sominsky Deborah M. Hodgson 《Synapse (New York, N.Y.)》2013,67(6):290-299
Brain inflammation in early life has been proposed to play important roles in the development of anxiety and psychosis‐related behaviors in adulthood, behaviors that rely on the integrity of dopamine and/or serotonin systems. Moreover recent behavioral and anatomical evidence suggests involvement of CB1 receptors in the control of emotion and mood. In this study, we determined the effects of neonatal LPS treatment on dopamine, serotonin, and cannabinoid receptor binding in adulthood. Rats were treated with the bacterial endotoxin lipopolysaccharide (LPS) on postnatal day (PND) 3 and 5. Dopamine D1, D2, serotonin 5HT1A, 5HT2A, and serotonin transporter and cannabinoid CB1 receptor binding across several brain regions were measured autoradiographically in adulthood (PND 85). Neonatal LPS treatment caused a significant increase in dopamine D2 in the nucleus accumbens and olfactory tubercle, a decrease in 5HT1A receptor binding in the hippocampus CA1 and ventromedial hypothalamus. A decrease in CB1 receptor binding after neonatal LPS was observed in the amygdala. Neonatal LPS had no significant impact on dopamine D1, serotonin 5HT2A or serotonin transporter binding in any of the brain regions examined. Our results suggest long lasting, region specific effects and differential impact on dopamine, serotonin and cannabinoid receptor systems following neonatal inflammation, that may form the basis for compromised anxiety and psychosis related behaviors. Synapse, 2013. © 2013 Wiley Periodicals, Inc. 相似文献
996.
Background: Quantitative light‐induced fluorescence (QLF) and digital photography (DP) have been proposed as clinical methods for measuring changes in enamel mineral content. The aim of this study was to compare the ability of QLF and DP with the in vitro gold standard transverse microradiography (TMR) to measure the remineralization of enamel subsurface lesions. Methods: Subsurface lesions were formed in enamel (n = 40) and exposed to remineralization solutions for 10 days. Changes were analysed by DP, QLF and TMR to determine percentage changes in luminescence (%L), fluorescence (%F) and mineral content (%R), respectively and correlation between these parameters determined. Results: The correlations between TMR and QLF (r = 0.63), TMR and DP (r = 0.59), and DP and QLF (r = 0.64) were all moderate but statistically significant (p < 0.001). The variability in %L and, to a lesser extent, %F values significantly impacted on the potential role of DP and QLF as methods by which mineral content changes produced by remineralization treatments could be accurately measured. Conclusions: Both QLF and DP provided data that correlated moderately with TMR data. QLF images were easier to analyse, free of glare and had less variability compared with those produced using DP. 相似文献
997.
998.
999.
The United States Department of Health and Human Services (HHS) leads the nation in preventing, preparing for, and responding to the adverse health effects of public health emergencies and disasters. In addition to biological, radiological and nuclear agents, the risk of a high consequence public health emergency due to the intentional and/or accidental release of chemical agents is a major growing concern of the US government. As such, the federal government is fully committed to address public health security threats posed by chemicals. To enhance chemical emergency preparedness and response, HHS oversees the interdepartmental research, advanced development, regulatory review and approval, procurement, and stockpiling of medical countermeasures (MCMs). Within the National Institute of Health (NIH/HHS), the National Institute of Allergy and Infectious Diseases (NIAID) is responsible for the fundamental research and early development of MCMs to prevent deaths and/or treat injuries during and after emergencies due to large scale chemical exposure. This commentary provides an overview of the NIAID/NIH Chemical Countermeasures Research Program (CCRP) and resources to facilitate the research, discovery, and early development of chemical MCMs. Available product development resources include research funding opportunities, expert advice from the NIH, and preclinical and efficacy service support cores to reduce opportunity costs and entry barriers for prospective developers interested in entering or accelerating the development of chemical MCMs. 相似文献