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   3195篇
  免费   175篇
  国内免费   2篇
  2023年   38篇
  2022年   57篇
  2021年   56篇
  2020年   79篇
  2019年   121篇
  2018年   135篇
  2017年   147篇
  2016年   168篇
  2015年   100篇
  2014年   125篇
  2013年   374篇
  2012年   210篇
  2011年   198篇
  2010年   122篇
  2009年   122篇
  2008年   140篇
  2007年   143篇
  2006年   112篇
  2005年   114篇
  2004年   111篇
  2003年   78篇
  2002年   78篇
  2001年   32篇
  2000年   42篇
  1999年   30篇
  1998年   31篇
  1997年   15篇
  1996年   19篇
  1995年   22篇
  1994年   19篇
  1993年   15篇
  1992年   26篇
  1991年   14篇
  1990年   18篇
  1989年   16篇
  1988年   17篇
  1987年   8篇
  1986年   16篇
  1985年   22篇
  1984年   8篇
  1983年   9篇
  1982年   11篇
  1981年   9篇
  1980年   10篇
  1979年   17篇
  1978年   10篇
  1977年   11篇
  1976年   8篇
  1975年   8篇
  1973年   9篇
排序方式: 共有3372条查询结果,搜索用时 15 毫秒
221.
Retrospective recall about children’s symptoms is used to establish early developmental patterns in clinical practice and is also utilised in child psychopathology research. Some studies have indicated that the accuracy of retrospective recall is influenced by life events. Our hypothesis was that an intervention: speech and language therapy, would adversely affect the accuracy of parent recall of early concerns about their child’s speech and language development. Mothers (n?=?5,390) reported on their child’s speech development (child male to female ratio = 50:50) when their children were aged 18 or 30 months, and also reported on these early concerns retrospectively, 10 years later, when their children were 13 years old. Overall reliability of retrospective recall was good, 86 % of respondents accurately recalling their earlier concerns. As hypothesised, however, the speech and language intervention was strongly associated with inaccurate retrospective recall about concerns in the early years (Relative Risk Ratio = 19.03; 95 % CI:14.78–24.48). Attendance at speech therapy was associated with increased recall of concerns that were not reported at the time. The study suggests caution is required when interpreting retrospective reports of abnormal child development as recall may be influenced by intervening events.  相似文献   
222.
Automating integrative complexity is fraught with many challenges. To address these challenges, we discuss the tension between a specificity approach and a more flexible multiple‐pass approach, the multifaceted nature of the complexity construct, the gold standard for complexity measurement, the difficulty of human scoring and its consequences for automation, and some ways forward for creating the best complexity measurements. In so doing, we present new data demonstrating (1) initial evidence for the validity of a new automated system for measuring two different forms of complexity (elaborative and dialectical), (2) the danger of constructing measurements in a purely ad hoc fashion that ignores prospective testing, (3) human‐to‐computer correspondence is in part a function of human‐to‐human correspondence, (4) human‐to‐computer correspondence increases systematically as one uses tests with larger units of analysis, and (5) the lack of correspondence of different systems (both human and automated) may occur in part because they were designed for different units of analysis.  相似文献   
223.
224.
This article proposes a new, more efficient method to compute the minus two log likelihood, its gradient, and the Hessian for structural equation models (SEMs) in reticular action model (RAM) notation. The method exploits the beneficial aspect of RAM notation that the matrix derivatives used in RAM are sparse. For an SEM with K variables, P parameters, and P′ entries in the symmetrical or asymmetrical matrix of the RAM notation filled with parameters, the asymptotical run time of the algorithm is O(P?′?K 2?+?P 2 K 2?+?K 3). The naive implementation and numerical implementations are both O(P 2 K 3), so that for typical applications of SEM, the proposed algorithm is asymptotically K times faster than the best previously known algorithm. A simulation comparison with a numerical algorithm shows that the asymptotical efficiency is transferred to an applied computational advantage that is crucial for the application of maximum likelihood estimation, even in small, but especially in moderate or large, SEMs.  相似文献   
225.
In hindsight, people often perceive events to be more inevitable and foreseeable than in foresight. According to Causal Model Theory (Nestler et al. in J Exp Psychol Learn Mem Cogn 34: 1043–1054, 2008), causal explanations are crucial for such hindsight distortions to occur. The present study provides further empirical support for this notion but extends previous findings in several ways. First, ecologically valid materials were used. Second, the effect of causal information on hindsight distortions was investigated in the realm of previously known events. Third, cross-cultural differences in reasoning (analytic vs. holistic) were taken into account. Specifically, German and Vietnamese participants in our study were presented with Wikipedia articles about the nuclear power plant in Fukushima Daiichi, Japan. They read either the version that existed before the nuclear disaster unfolded (Version 1) or the article that existed 8 weeks after the catastrophe commenced (Version 2). Only the latter contained elaborations on causal antecedents and therefore provided an explanation for the disaster. Reading that version led participants to perceive the nuclear disaster to be more likely inevitable and foreseeable when compared to reading Version 1. Cultural background did not exert a significant effect on these perceptions. Hence, hindsight distortions were obtained for ecologically valid materials even if the event was already known. Implications and directions for future research are discussed.  相似文献   
226.
Fathers' and mothers' views on mothers' satisfaction with paternal behaviour as well as the respective processes of origination were studied in 393 cohabiting couples from three different stages of the family life cycle. Data on paternal competence and the couples' relationship characteristics were included as predictors in multiple regression analyses, and the stages of the family life cycle were taken into account with multigroup regression analyses. Results showed that the mothers were more satisfied with paternal behaviour than the fathers thought the mothers were. Moreover, mothers were satisfied when the fathers were willing to spend time with the child, whereas fathers thought that their partners were satisfied when they were able to establish and maintain a relationship with the child. Couple relationship satisfaction had a consistent impact on fathers' views, whereas it was not relevant to mothers' views unless the oldest child had reached adolescence.  相似文献   
227.
The concept of Granger causality can be used to examine putative causal relations between two series of scores. Based on regression models, it is asked whether one series can be considered the cause for the second series. In this article, we propose extending the pool of methods available for testing hypotheses that are compatible with Granger causation by adopting a configural perspective. This perspective allows researchers to assume that effects exist for specific categories only or for specific sectors of the data space, but not for other categories or sectors. Configural Frequency Analysis (CFA) is proposed as the method of analysis from a configural perspective. CFA base models are derived for the exploratory analysis of Granger causation. These models are specified so that they parallel the regression models used for variable-oriented analysis of hypotheses of Granger causation. An example from the development of aggression in adolescence is used. The example shows that only one pattern of change in aggressive impulses over time Granger-causes change in physical aggression against peers.  相似文献   
228.
Whereas the visual modality tends to dominate over the auditory modality in bimodal spatial perception, the auditory modality tends to dominate over the visual modality in bimodal temporal perception. Recent results suggest that the visual modality dominates bimodal spatial perception because spatial discriminability is typically greater for the visual than for the auditory modality; accordingly, visual dominance is eliminated or reversed when visual-spatial discriminability is reduced by degrading visual stimuli to be equivalent or inferior to auditory spatial discriminability. Thus, for spatial perception, the modality that provides greater discriminability dominates. Here, we ask whether auditory dominance in duration perception is similarly explained by factors that influence the relative quality of auditory and visual signals. In contrast to the spatial results, the auditory modality dominated over the visual modality in bimodal duration perception even when the auditory signal was clearly weaker, when the auditory signal was ignored (i.e., the visual signal was selectively attended), and when the temporal discriminability was equivalent for the auditory and visual signals. Thus, unlike spatial perception, where the modality carrying more discriminable signals dominates, duration perception seems to be mandatorily linked to auditory processing under most circumstances.  相似文献   
229.
230.
The dual systems model of adolescent risk‐taking portrays the period as one characterized by a combination of heightened sensation seeking and still‐maturing self‐regulation, but most tests of this model have been conducted in the United States or Western Europe. In the present study, these propositions are tested in an international sample of more than 5000 individuals between ages 10 and 30 years from 11 countries in Africa, Asia, Europe and the Americas, using a multi‐method test battery that includes both self‐report and performance‐based measures of both constructs. Consistent with the dual systems model, sensation seeking increased between preadolescence and late adolescence, peaked at age 19, and declined thereafter, whereas self‐regulation increased steadily from preadolescence into young adulthood, reaching a plateau between ages 23 and 26. Although there were some variations in the magnitude of the observed age trends, the developmental patterns were largely similar across countries.  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