首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3688篇
  免费   232篇
  国内免费   40篇
耳鼻咽喉   29篇
儿科学   140篇
妇产科学   24篇
基础医学   512篇
口腔科学   21篇
临床医学   244篇
内科学   327篇
皮肤病学   12篇
神经病学   1288篇
特种医学   76篇
外科学   168篇
综合类   314篇
预防医学   291篇
眼科学   51篇
药学   293篇
  1篇
中国医学   119篇
肿瘤学   50篇
  2024年   7篇
  2023年   40篇
  2022年   105篇
  2021年   117篇
  2020年   115篇
  2019年   127篇
  2018年   124篇
  2017年   149篇
  2016年   155篇
  2015年   114篇
  2014年   247篇
  2013年   383篇
  2012年   177篇
  2011年   231篇
  2010年   171篇
  2009年   174篇
  2008年   196篇
  2007年   184篇
  2006年   165篇
  2005年   130篇
  2004年   94篇
  2003年   96篇
  2002年   63篇
  2001年   45篇
  2000年   45篇
  1999年   51篇
  1998年   30篇
  1997年   34篇
  1996年   28篇
  1995年   29篇
  1994年   21篇
  1993年   29篇
  1992年   14篇
  1991年   28篇
  1990年   17篇
  1989年   25篇
  1988年   18篇
  1987年   22篇
  1986年   17篇
  1985年   26篇
  1984年   27篇
  1983年   7篇
  1982年   12篇
  1981年   11篇
  1980年   14篇
  1979年   9篇
  1978年   11篇
  1977年   5篇
  1976年   8篇
  1974年   7篇
排序方式: 共有3960条查询结果,搜索用时 0 毫秒
91.
BackgroundDaytime and nighttime sleep disturbances and cognitive impairment occur frequently in Parkinson's disease (PD), but little is known about the interdependence of these non-motor complications. Thus, we examined the relationships among excessive daytime sleepiness, nighttime sleep quality and cognitive impairment in PD, including severity and specific cognitive deficits.MethodsNinety-three PD patients underwent clinical and neuropsychological evaluations including the Epworth Sleepiness Scale (ESS) and Pittsburgh Sleep Quality Index (PSQI). Patients were classified as having normal cognition (PD-NC), mild cognitive impairment (PD-MCI), or dementia (PDD) using recently proposed Movement Disorder Society PD-MCI and PDD criteria. Relationships between the sleep and cognitive measures and PD cognitive groups were examined.ResultsThe PD cohort included PD-NC (n = 28), PD-MCI (n = 40), and PDD (n = 25) patients. ESS scores, as a measure of daytime sleepiness, were significantly worse (p = 0.005) in cognitively impaired PD patients, particularly PDD patients. ESS scores correlated significantly with Mini-Mental State Examination scores and also with cognitive domain scores for attention/working memory, executive function, memory, and visuospatial function. In contrast, PSQI scores, as a measure of nighttime sleep quality, neither differed among cognitive groups nor correlated with any cognitive measures.ConclusionsDaytime sleepiness in PD, but not nighttime sleep problems, is associated with cognitive impairment in PD, especially in the setting of dementia, and attention/working memory, executive function, memory, and visuospatial deficits. The presence of nighttime sleep problems is pervasive across the PD cognitive spectrum, from normal cognition to dementia, and is not independently associated with cognitive impairment or deficits in cognitive domains.  相似文献   
92.
Declarative memory is a long-term store for facts, concepts and words. Procedural memory subserves the learning and control of sensorimotor and cognitive skills, including the mental grammar. In this study, we report a single-case study of a mild aphasic patient who showed procedural deficits in the presence of preserved declarative memory abilities. We administered several experiments to explore rule application in morphology, syntax and number processing. Results partly support the differentiation between declarative and procedural memory. Moreover, the patient's performance varied according to the domain in which rules were to be applied, which underlines the need for more fine-grained distinctions in cognition between procedural rules.  相似文献   
93.
The current study examined how hemispheric asymmetries in perceptual processing affect control processes associated with voluntary task choice during multitask behaviour. In a voluntary task-switching paradigm, where participants are free to choose which task to perform on each trial, participants identified either the global-or local-level features of hierarchical stimuli presented to either the left or right visual field. Hemispheric asymmetries in perception of lateralised hierarchical stimuli were evident in reaction times. Importantly, participants were more likely to categorise the stimulus in line with the processing efficiency of the hemisphere to which it was initially presented: the global task for left visual field presentation and the local task for right visual field presentation. Perceptual processing characteristics influence control processes associated with task choice in multitask environments.  相似文献   
94.
Age-related changes in visual spatial biases in children, young adults, and older adults were studied with unilateral and bilateral stimulus conditions in fast-paced linguistic and non-linguistic attention tasks. Only rightward spatial biases were observed. The incidence of the biases changed as a function of age: in childhood and in old age the rightward spatial biases were more common than in young adulthood. The present rightward spatial biases were similar to those observed in the corresponding auditory spatial linguistic and non-linguistic attention tests (Takio, Koivisto, Laukka, & Hämäläinen, 2011) and in the dichotic listening forced-attention task (Takio et al., 2009). We suggest that the multimodal rightward spatial bias observed under intensive attentional load is related to a right hemispace preference and modulated by age-dependent changes in executive functions.  相似文献   
95.
Strategies for the detection of possible malingering have largely taken two forms. First is the development and validation of domain-specific measures of malingering designed specifically for the detection of malingering (e.g., Test Of Memory Malingering, Word Memory Test, and Word Completion Memory Test). The second has been the development and evaluation of performance patterns and cutoff scores applicable to commonly used neuropsychological instruments. Two such instruments that have been examined are the Wisconsin Card Sorting Test (WCST) and the California Verbal Learning Test (CVLT). While several studies propose possible cutoff scores and actuarial judgement strategies for these tests, the specificity of these strategies within older, nonimpaired adults has not been established. Without proper evaluation of potential age-related effects within these strategies, the actual utility of the strategies within suspected malingerers who are older adults is unknown. Therefore, the present study was conducted to evaluate the specificity of the proposed strategies for detecting possible malingering with the WCST and the CVLT in a sample of older, community-dwelling, nonimpaired adults. The results suggest that the currently existing WCST formulas may have limited utility for the detection of malingering with older adults while the CVLT strategies do appear to have potential clinical utility. The potential of these formulas for use with older adults is discussed.  相似文献   
96.
The presented study aimed to advance understanding of the reasons for non-suicidal self-harm (NSSH) in adult male offenders, with and without borderline personality traits. 179 offenders completed self-report measures of NSSH and other clinical constructs, with 42 being identified as having self-harmed. Results were consistent with past research and supported the relative importance of intrapersonal over interpersonal functions, but also highlight that self-harm is performed rarely for one type of reason. The results also show that the presence of borderline personality traits increases the likelihood of endorsing a range of interpersonal reasons. These findings highlight the importance of understanding the range of reasons for engaging in NSSH to help manage the behaviour within the prison  相似文献   
97.
Despite their common use in neuropsychological evaluation, little is known about the differential contribution of executive functioning to visual memory tests. In this study, hierarchical regression was used to determine the role of executive functioning on the Visual Reproduction subtest of the Wechsler Memory Scale—Third Edition, and the Rey-Osterrieth Complex Figure (ROCF) in a mixed neurological sample of 193 patients. Executive functioning was predictive of Visual Reproduction but not ROCF recall variables after accounting for demographic variables and global cognitive functioning. Only executive tests with a visuospatial component, the Trail-Making Test Part B and Wisconsin Card Sorting Test perseverative responses, were predictive of recall of Visual Reproduction stimuli. Organization of the ROCF was predictive of both Visual Reproduction and ROCF recall. These findings increase our understanding of the executive contribution to two common visual memory tests and may aid in the clinical interpretation of seemingly discrepant visual memory performance.  相似文献   
98.
The Behavior Rating Inventory of Executive Function-Preschool Version (BRIEF-P; Gioia, Espy, & Isquith, 2003 Gioia , G. A. , Espy , K. A. , & Isquith , P. K. ( 2003 ). The Behavior Rating Inventory of Executive Function-Preschool version (BRIEF-P) . Odessa , FL : Psychological Assessment Resources . [Google Scholar]) was developed to assess executive function (EF) behaviors in children aged 2 to 5 years. We compared parent ratings of 25 preschool children with ADHD to 25 age-, sex-, and SES-matched controls from the BRIEF-P standardization sample. Children with ADHD were rated significantly higher than controls (p < .01) on all five primary scales (Inhibit, Shift, Emotional Control, Working Memory, Plan/Organize), and on all four indices (Inhibitory Self Control, Flexibility, Emerging Metacognition, General Executive Composite). The largest effect size was on the Working Memory scale. All five BRIEF-P clinical scales were significantly intercorrelated in the control group, and seven of ten scale intercorrelations were significant in the ADHD group. Within the ADHD group, the BRIEF-P Index scores were significantly correlated with ratings on the Conners' Parent Rating Scale, but only moderately correlated with an estimate of Verbal IQ. The BRIEF-P had low, non-significant correlations with performance-based measures of EF, and patterns of correlations were not significantly different than those between the BRIEF-P and non-EF measures (sensorimotor, receptive vocabulary). Similar to its predecessor, the BRIEF-P is sensitive to symptoms of ADHD, but appears to measure different elements of EF than those tapped by performance-based measures.  相似文献   
99.
Performance on the Push-Turn-Taptap (PTT) task has been shown to be a strong predictor of concurrent everyday functioning. This study utilized a prospective, longitudinal design to evaluate the PTT task for predicting future performance on a behavioral assessment of everyday functioning. The PTT task was compared to other measures of executive functioning as well as general cognition in terms of administration time and ability to identify participants who evidenced functional decline. A total of 50 community-dwelling older adults (ages 58–87) completed the PTT task, Mattis Dementia Rating Scale, Geriatric Depression Scale, Behavioral Dyscontrol Scale, Delis-Kaplan Executive Function System, and Timed Instrumental Activities of Daily Living. Baseline PTT performance (a) was highly correlated with an objective measure of everyday functioning after approximately one year (r?=??.497, p?<?.001), (b) was associated with changes in follow-up functioning, F(3, 46)?=?3.15, p?=?.03, (c) was a better predictor of future functional status than a longer battery of EF, and (d) reliably identified individuals with the greatest magnitude of functional decline. The PTT tasks may provide a particularly advantageous method of predicting future changes in everyday functioning in older adults.  相似文献   
100.
Executive function (EF) deficits in schizophrenia (SZ) are well documented, although much less is known about patterns of EF deficits and their association to differential impairments in everyday functioning. The present study empirically defined SZ groups based on measures of various EF abilities and then compared these EF groups on everyday action errors. Participants (n?=?45) completed various subtests from the Delis–Kaplan Executive Function System (D-KEFS) and the Naturalistic Action Test (NAT), a performance-based measure of everyday action that yields scores reflecting total errors and a range of different error types (e.g., omission, perseveration). Results of a latent class analysis revealed three distinct EF groups, characterized by (a) multiple EF deficits, (b) relatively spared EF, and (c) perseverative responding. Follow-up analyses revealed that the classes differed significantly on NAT total errors, total commission errors, and total perseveration errors; the two classes with EF impairment performed comparably on the NAT but performed worse than the class with relatively spared EF. In sum, people with SZ demonstrate variable patterns of EF deficits, and distinct aspects of these EF deficit patterns (i.e., poor mental control abilities) may be associated with everyday functioning capabilities.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号