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   1292篇
  免费   200篇
  国内免费   308篇
  2024年   3篇
  2023年   29篇
  2022年   26篇
  2021年   38篇
  2020年   51篇
  2019年   41篇
  2018年   49篇
  2017年   69篇
  2016年   47篇
  2015年   47篇
  2014年   58篇
  2013年   129篇
  2012年   101篇
  2011年   111篇
  2010年   114篇
  2009年   107篇
  2008年   116篇
  2007年   120篇
  2006年   105篇
  2005年   99篇
  2004年   68篇
  2003年   44篇
  2002年   41篇
  2001年   25篇
  2000年   25篇
  1999年   20篇
  1998年   7篇
  1997年   14篇
  1996年   5篇
  1995年   11篇
  1994年   5篇
  1993年   9篇
  1992年   6篇
  1991年   5篇
  1990年   5篇
  1989年   9篇
  1988年   6篇
  1987年   5篇
  1986年   3篇
  1985年   5篇
  1983年   2篇
  1982年   3篇
  1981年   2篇
  1980年   2篇
  1975年   1篇
  1973年   4篇
  1971年   1篇
  1969年   1篇
  1968年   1篇
  1964年   1篇
排序方式: 共有1800条查询结果,搜索用时 15 毫秒
101.
Individuals with schizophrenia spectrum personality disorders (SSPD) and schizophrenia show similar cognitive impairments. The authors examined the contributions of SSPD symptoms and familial risk for schizophrenia to impairments on the Continuous Performance Test--Identical Pairs Version. Participants included 103 schizophrenia patients, 66 first-degree relatives (29 SSPD), and 103 community controls (26 SSPD) screened for family history of psychosis. Patients and SSPD relatives performed significantly worse than non-SSPD relatives and SSPD and non-SSPD community controls. No differences in performance were observed among non-SSPD relatives and SSPD and non-SSPD community controls. Results suggest a continuum in which risk for schizophrenia-related cognitive impairments is highest among patients and SSPD relatives, intermediate among non-SSPD relatives, and lowest among SSPD and non-SSPD community controls. Results suggest that SSPD in the absence of a family history of psychosis may be a phenocopy.  相似文献   
102.
Research findings show that there is marked variability in children's response to parental separation, but few studies identify the sources of this variation. This prospective longitudinal study examines the factors modifying children's adjustment to parental separation in a community sample of 5,635 families in England. Children's behavioral/emotional problems were assessed when children were aged 47 and 81 months; marital quality, maternal depression, socioeconomic circumstances, and demographic variables were assessed prior to the separation from maternal report. Results indicated that 346 mothers separated from their partners in the 3-year period. Preseparation differences were found for measures of family process and parent risk factors, with effect sizes ranging from small to trivial. Parental separation was associated with a significant but modest increase in behavioral/emotional problems, independent of marital quality, maternal depression, socioeconomic circumstances, and demographic variables. Moderation analyses showed that children of cohabiting parents had a greater increase in adjustment problems following parental separation than children of married parents. Further research elucidating the factors that moderate children's adjustment to parental separation is needed to improve our understanding of who may most likely benefit from preventive interventions.  相似文献   
103.
Human visual attention operates in a context that is complex, social and dynamic. To explore this, we recorded people taking part in a group decision-making task and then showed video clips of these situations to new participants while tracking their eye movements. Observers spent the majority of time looking at the people in the videos, and in particular at their eyes and faces. The social status of the people in the clips had been rated by their peers in the group task, and this status hierarchy strongly predicted where eye-tracker participants looked: high-status individuals were gazed at much more often, and for longer, than low-status individuals, even over short, 20-s videos. Fixation was temporally coupled to the person who was talking at any one time, but this did not account for the effect of social status on attention. These results are consistent with a gaze system that is attuned to the presence of other individuals, to their social status within a group, and to the information most useful for social interaction.  相似文献   
104.
Most Chinese characters are composed of a semantic radical on the left and a phonetic radical on the right. The semantic radical provides the semantic information; the phonetic radical provides information concerning the pronunciation of the whole character. The pseudo‐characters in the study consisted of different sub‐lexical parts of real Chinese characters and consequently they also had the semantic radical and the phonetic radical. But they were not readable and had no actual meaning. In order to investigate the spatiotemporal cortical activation patterns underlying the orthographic, phonological and semantic processing of Chinese characters, we used event‐related brain potentials (ERPs) to explore the processing of Chinese characters and pseudo‐characters when 14 healthy Chinese college students viewed the characters passively. Results showed that both Chinese characters and pseudo‐characters elicited an evident negative potential peaking around 120 ms (N120), which appeared to reflect initial orthographic distinction and evaluation. Then, Chinese pseudo‐characters elicited a more positive ERP deflection (P220) than did Chinese characters 200–250 ms after onset of the stimuli. It was similar to the recognition potential (RP) and might reflect the integration processes of phonological and semantic processing on the basis of early orthographic information. Dipole source analysis of the difference wave (pseudo‐characters minus characters) indicated that a generator localized in the left temporal‐occipital junction contributed to this effect, which was possibly related to phonological and perceptual–semantic information integration. Between 350–450 ms, a greater negativity (N360) in pseudo‐characters as compared to characters was found over midline fronto‐central scalp regions. Dipole analysis localized the generator of N360 in the right parahippocampal cortex. Therefore, the N360 might be an N400 component and reflect the higher‐level semantic activation on the basis of orthographic, phonological and perceptual–semantic processing.  相似文献   
105.
Archival data (N = 1,048 women, 1,136 men) from a mental health survey of college students were used to investigate incidence of nonsuicidal self-injury (NSSI), including cutting. Significant levels (defined as 4-5 lifetime incidents) were found in 9.3% of women and 5.3% of men. The Counseling Center Assessment for Psychological Symptoms (a global symptom inventory) and an assessment of trauma had been field tested with this sample. We randomly partitioned half of these data into a holdout sample and used the remainder to develop an NSSI screening inventory that included (a) 5 women's screening items, including 1 item to assess trauma experienced; (b) 11 men's screening items; and (c) 12 items common to men and women, including depression, dissociation, anger, unwanted thoughts, nightmares or flashbacks, and having witnessed trauma. Logistic regression and receiver-operating characteristic curve analysis suggested the inventory significantly discriminated NSSI men and women in the holdout sample, p < .001. Cutoff scores were identified to correctly classify about 48% of the true positive male and female NSSI cases, with false positive rates of 13.2% and 8.4% for women and men, respectively.  相似文献   
106.
Self-Efficacy and the Prediction of Domain-Specific Cognitive Abilities   总被引:1,自引:0,他引:1  
ABSTRACT We evaluated predictors of performance in 4 specific cognitive ability domains: verbal, numerical, spatial, and mechanical. The predictors were individual differences in self-efficacy beliefs, self-enhancement tendencies, and cross-domain abilities. Our university students' beliefs about their verbal, numerical, and spatial capabilities correlated well with their actual performance on standardized tests (verbal r =.33, numerical r =.27, spatial r =.36). In contrast, the students' self-efficacy for mechanical tasks did relatively poorly in predicting mechanical test performance ( r =.10). Most interesting were two other findings: (a) The best predictor of domain performance was level of cross-domain performance by far, even for mechanical tasks, and (b) self-enhancement tendencies added to cross-domain abilities and self-efficacy beliefs in the prediction of performance. The results are discussed in terms of possible mechanisms explaining how one's score on a maximal performance task can be affected by self-efficacy beliefs and self-enhancement tendencies.  相似文献   
107.
This paper studies changes of standard errors (SE) of the normal-distribution-based maximum likelihood estimates (MLE) for confirmatory factor models as model parameters vary. Using logical analysis, simplified formulas and numerical verification, monotonic relationships between SEs and factor loadings as well as unique variances are found. Conditions under which monotonic relationships do not exist are also identified. Such functional relationships allow researchers to better understand the problem when significant factor loading estimates are expected but not obtained, and vice versa. What will affect the likelihood for Heywood cases (negative unique variance estimates) is also explicit through these relationships. Empirical findings in the literature are discussed using the obtained results.  相似文献   
108.
多体素模式分析(multi-voxel pattern analysis,MVPA)是一种基于机器学习理论发展出来的新的功能磁共振数据分析技术。MVPA技术通过训练分类器,对由不同认知状态引起的多体素信号模式进行分类。与传统的基于单个体素的分析方法相比,该技术可更敏感地检测脑对认知状态的表征,并使得从神经信号解码认知状态成为可能。文章介绍MVPA技术的基本原理、分析步骤以及可以用MVPA来解决的科学问题,并对应用中可能面临的问题提供了参考建议。  相似文献   
109.
大学生利他动机的调查研究   总被引:8,自引:0,他引:8  
研究的主要目的是对大学生利他动机进行调查分析。测量工具为利己性利他动机量表和利他性利他动机量表。被试取自北京5所高校的大学生1920名。结果显示:57.4%的大学生报告高度利己性利他动机。63.2%的大学生报告高度利他性利他动机。性别、独生子女、家庭地点等因素均同大学生利己性利他动机无关。独生子女、家庭地点、学校性质同大学生利他性利他动机有显著关系。  相似文献   
110.
Abstract

A quasicrystalline Al-Fe phase has been formed by room-temperature ion mixing of AI-Fe multiple layers with no additional postannealing. The quasicrystalline phase was dispersed as grain in an amorphous matrix. The size of the grains was about 10-30nm, and the composition was determined to be Al80Fe20. The structure of the quasicrystalline phase was identified by calculating some 20 sharp diffraction rings in the selected-area diffraction pattern and found to be similar to that of the rapidly quenched AI-Mn quasicrystalline phase.  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