全文获取类型
收费全文 | 28477篇 |
免费 | 2430篇 |
国内免费 | 501篇 |
专业分类
耳鼻咽喉 | 482篇 |
儿科学 | 1139篇 |
妇产科学 | 488篇 |
基础医学 | 2360篇 |
口腔科学 | 1216篇 |
临床医学 | 2828篇 |
内科学 | 4619篇 |
皮肤病学 | 451篇 |
神经病学 | 7933篇 |
特种医学 | 394篇 |
外科学 | 1529篇 |
综合类 | 1989篇 |
现状与发展 | 3篇 |
一般理论 | 1篇 |
预防医学 | 3066篇 |
眼科学 | 205篇 |
药学 | 1945篇 |
7篇 | |
中国医学 | 432篇 |
肿瘤学 | 321篇 |
出版年
2024年 | 75篇 |
2023年 | 711篇 |
2022年 | 716篇 |
2021年 | 1518篇 |
2020年 | 1437篇 |
2019年 | 1354篇 |
2018年 | 1331篇 |
2017年 | 1279篇 |
2016年 | 1210篇 |
2015年 | 1089篇 |
2014年 | 1803篇 |
2013年 | 2700篇 |
2012年 | 1402篇 |
2011年 | 1665篇 |
2010年 | 1265篇 |
2009年 | 1334篇 |
2008年 | 1352篇 |
2007年 | 1222篇 |
2006年 | 1071篇 |
2005年 | 854篇 |
2004年 | 758篇 |
2003年 | 781篇 |
2002年 | 609篇 |
2001年 | 446篇 |
2000年 | 390篇 |
1999年 | 347篇 |
1998年 | 334篇 |
1997年 | 295篇 |
1996年 | 226篇 |
1995年 | 216篇 |
1994年 | 182篇 |
1993年 | 167篇 |
1992年 | 178篇 |
1991年 | 128篇 |
1990年 | 136篇 |
1989年 | 80篇 |
1988年 | 95篇 |
1987年 | 83篇 |
1986年 | 71篇 |
1985年 | 101篇 |
1984年 | 74篇 |
1983年 | 55篇 |
1982年 | 47篇 |
1981年 | 44篇 |
1980年 | 32篇 |
1979年 | 36篇 |
1978年 | 32篇 |
1977年 | 26篇 |
1976年 | 15篇 |
1975年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
992.
993.
《Brain stimulation》2021,14(5):1393-1403
BackgroundNumerous neuromodulatory therapies are currently under investigation or in clinical use for the treatment of psychiatric conditions.Objective/hypothesisWe sought to catalogue past and present human research studies on psychiatric neuromodulation and identify relevant trends in this field.MethodsClinicalTrials.gov (https://www.clinicaltrials.gov/) and the International Clinical Trials Registry Platform (https://www.who.int/ictrp/en/) were queried in March 2020 for trials assessing the outcome of neuromodulation for psychiatric disorders. Relevant trials were categorized by variables such as neuromodulation modality, country, brain target, publication status, design, and funding source.ResultsFrom 72,086 initial search results, 1252 unique trials were identified. The number of trials registered annually has consistently increased. Half of all trials were active and a quarter have translated to publications. The largest proportion of trials involved depression (45%), schizophrenia (18%), and substance use disorders (14%). Trials spanned 37 countries; China, the second largest contributor (13%) after the United States (28%), has increased its output substantially in recent years. Over 75% of trials involved non-convulsive non-invasive modalities (e.g., transcranial magnetic stimulation), while convulsive (e.g., electroconvulsive therapy) and invasive modalities (e.g., deep brain stimulation) were less represented. 72% of trials featured approved or cleared interventions. Characteristic inter-modality differences were observed with respect to enrollment size, trial design/phase, and funding. Dorsolateral prefrontal cortex accounted for over half of focal neuromodulation trial targets. The proportion of trials examining biological correlates of neuromodulation has increased.Conclusion(s)These results provide a comprehensive overview of the state of psychiatric neuromodulation research, revealing the growing scope and internationalism of this field. 相似文献
994.
Spinal dysraphic lesions due to focal nondisjunction in primary neurulation are commonly encountered in paediatric neurosurgery, but the “fog-of-war” on these conditions was only gradually dispersed in the past 10 years by the works of the groups led by the senior author and Prof. Kyu-Chang Wang. It is now clear that limited dorsal myeloschisis and congenital spinal dermal sinus tract are conditions at the two ends of a spectrum; and mixed lesions of them with various configurations exist. This review article summarizes the current understanding of these conditions’ embryogenetic mechanisms, pathological anatomy and clinical manifestations, and their management strategy and surgical techniques. 相似文献
995.
996.
So Yoon Kim Young Ah Kim Da-Yea Song Guiyoung Bong Jong-myeong Kim Joo Hyun Kim Hee Jeong Yoo 《Psychiatry investigation》2021,18(3):257
Objective This study examined how state and trait anxiety of adolescents with autism spectrum disorders (ASD) are associated with their demographic characteristics, repetitive and restricted behaviors (RRBs), and internalizing and externalizing problem behaviors. Methods A total of 96 participants with ASD (mean age=14.30 years; 91 males) completed a battery of tests including the State/Trait Anxiety Inventory (STAI), the Autism Diagnostic Interview-Revised, the Social Responsiveness Scale (SRS), and a cognitive test measuring intelligence quotient (IQ). Participants’ parents completed the Child Behavior Checklist (CBCL). Pearson’s correlations among age, IQ, two subscales of the STAI (i.e., STAIS and STAIT, measuring self-reported state and trait anxiety, respectively), and the Anxiety subscale of CBCL (i.e., CBCL-Anxiety, measuring parent-reported trait anxiety) were computed. Subsequently, Pearson’s correlations were computed among the three anxiety measures, RRBs, and problem behaviors, while controlling for participants’ age and IQ. Results The STAIS and CBCL-Anxiety were both significantly correlated with higher age, sensory sensitivity, depressive symptoms, somatic complaints, and aggressive behaviors. All three anxiety variables were significantly and positively correlated with total SRS RRB scores. Additionally, the STAIS and STAIT were significantly associated with more severe Compulsion/Adherence behaviors, and the CBCL-Anxiety was also significantly associated with more severe Rule-breaking Behaviors. Conclusion Self-reported state anxiety showed association patterns similar to those of parent-reported trait anxiety. Future studies investigating the precise operationalization of different anxiety instruments are needed to accurately measure the anxiety of adolescents with ASD. 相似文献
997.
Anxiety disorders are the most prevalent psychiatric condition among youth, with symptoms commonly emerging prior to or during adolescence. Delineating neurodevelopmental trajectories associated with anxiety disorders is important for understanding the pathophysiology of pediatric anxiety and for early risk identification. While a growing literature has yielded valuable insights into the nature of brain structure and function in pediatric anxiety, progress has been limited by inconsistent findings and challenges common to neuroimaging research. In this review, we first discuss these challenges and the promise of ‘big data’ to map neurodevelopmental trajectories in pediatric anxiety. Next, we review evidence of age-related differences in neural structure and function among anxious youth, with a focus on anxiety-relevant processes such as threat and safety learning. We then highlight large-scale cross-sectional and longitudinal studies that assess anxiety and are well positioned to inform our understanding of neurodevelopment in pediatric anxiety. Finally, we detail relevant challenges of ‘big data’ and propose future directions through which large publicly available datasets can advance knowledge of deviations from normative brain development in anxiety. Leveraging ‘big data’ will be essential for continued progress in understanding the neurobiology of pediatric anxiety, with implications for identifying markers of risk and novel treatment targets. 相似文献
998.
999.
ObjectivesThis research explores the use of polymer brushes for surface treatment of fillers used in polymer-based dental restoratives with focus on shrinkage stress reduction. The influence of interfacial reactive groups on shrinkage stress is explored.MethodsOligomers of varying lengths and with varying number of reactive groups along the length were synthesized by modifying commercial oligomers. Surface of silica fillers (OX50) was treated with methylaminopropyltrimethoxysilane and this was further reacted with the synthesized oligomers to obtain a series of polymer brushes on the surface. Fillers modified with γ-methacryloxypropyltrimethoxysilane were used as a control. Filler surface treatment was confirmed using diffuse reflectance spectroscopy and thermogravimetric analysis. Fillers were added at 30 wt % to a resin made of BisGMA/TEGDMA and polymerization kinetics, shrinkage stress, volumetric shrinkage, flexural strength and modulus, viscosity were measured.ResultsComposites with polymer brush functionalized fillers showed up to a 30 % reduction in shrinkage stress as compared to the control, with no reduction in flexural strength and modulus. Shrinkage stress reduced with increasing length of the polymer brush and increased with increase in number of reactive groups along the length of the polymer brush.SignificanceThe interface between inorganic fillers and an organic polymer matrix has been utilized to reduce shrinkage stress in a composite with no compromise in mechanical properties. This study gives insights into the stress development mechanism at the interface. 相似文献
1000.
Naser Azmi Rushdi Khayat BDS MSc Nir Shpack DMD MSc Alona Emodi Perelman DMD Pessia Friedman-Rubin DMD Reem Yaghmour MSc 《Cranio : the journal of craniomandibular practice》2021,39(1):29-34
ABSTRACT Objective: To assess the prevalence of temporomandibular disorders (TMDs) and posterior crossbite and/or deep bite and any possible association between them. Methods: One thousand-nineteen adolescents responded to a questionnaire regarding oral habits and TMD symptoms. Afterwards, they were diagnosed according to the Axis I of the DC/TMD and underwent a dental examination. The chi-square test was used for statistical analysis. Results: A significant association was found between posterior crossbite and some TMD diagnosis, but no association was found between deep bite and TMD, nor between occlusal diagnosis and bruxism. TMDs were more prevalent in girls. There was a significant sex difference (more among females) in the prevalence of painful TMDs. Conclusion: Posterior crossbite in the adolescent population analyzed may be related to TMDs, in contrary to deep-bite. The presence of posterior crossbite may have different impact on TMD findings between the sexes. 相似文献