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   363篇
  免费   22篇
  2023年   7篇
  2022年   8篇
  2021年   1篇
  2020年   11篇
  2019年   13篇
  2018年   15篇
  2017年   21篇
  2016年   12篇
  2015年   14篇
  2014年   14篇
  2013年   49篇
  2012年   17篇
  2011年   32篇
  2010年   17篇
  2009年   12篇
  2008年   16篇
  2007年   18篇
  2006年   15篇
  2005年   16篇
  2004年   11篇
  2003年   10篇
  2002年   8篇
  2001年   7篇
  2000年   2篇
  1999年   6篇
  1998年   3篇
  1997年   3篇
  1996年   3篇
  1995年   3篇
  1994年   4篇
  1991年   2篇
  1987年   2篇
  1986年   2篇
  1985年   2篇
  1983年   2篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1976年   1篇
  1969年   2篇
排序方式: 共有385条查询结果,搜索用时 359 毫秒
291.
After defining, for each many-sorted signature Σ = (S, Σ), the category Ter(Σ), of generalized terms for Σ (which is the dual of the Kleisli category for \mathbb TS{\mathbb {T}_{\bf \Sigma}}, the monad in Set S determined by the adjunction TS \dashv GS{{\bf T}_{\bf \Sigma} \dashv {\rm G}_{\bf \Sigma}} from Set S to Alg(Σ), the category of Σ-algebras), we assign, to a signature morphism d from Σ to Λ, the functor dà{{\bf d}_\diamond} from Ter(Σ) to Ter(Λ). Once defined the mappings that assign, respectively, to a many-sorted signature the corresponding category of generalized terms and to a signature morphism the functor between the associated categories of generalized terms, we state that both mappings are actually the components of a pseudo-functor Ter from Sig to the 2-category Cat. Next we prove that there is a functor TrΣ, of realization of generalized terms as term operations, from Alg(Σ) × Ter(Σ) to Set, that simultaneously formalizes the procedure of realization of generalized terms and its naturalness (by taking into account the variation of the algebras through the homomorphisms between them). We remark that from this fact we will get the invariance of the relation of satisfaction under signature change. Moreover, we prove that, for each signature morphism d from Σ to Λ, there exists a natural isomorphism θ d from the functor TrL °(Id ×dà){{{\rm Tr}^{\bf {\bf \Lambda}} \circ ({\rm Id} \times {\bf d}_\diamond)}} to the functor TrS °(d* ×Id){{\rm Tr}^{\bf \Sigma} \circ ({\bf d}^* \times {\rm Id})}, both from the category Alg(Λ) × Ter(Σ) to the category Set, where d* is the value at d of the arrow mapping of a contravariant functor Alg from Sig to Cat, that shows the invariant character of the procedure of realization of generalized terms under signature change. Finally, we construct the many-sorted term institution by combining adequately the above components (and, in a derived way, the many-sorted specification institution), but for a strict generalization of the standard notion of institution.  相似文献   
292.
It is generally assumed that the function of contingency learning is to predict the occurrence of important events in order to prepare for them. This assumption, however, has scarcely been tested. Moreover, the little evidence that is available suggests just the opposite result. People do not use contingency to prepare for outcomes, nor to predict their occurrence, although they do use it to infer the causal and predictive value of cues. By using both judgmental and behavioral data, we designed the present experiments as a further test for this assumption. The results show that—at least under certain conditions—people do use contingency to prepare for outcomes, even though they would still not use it to predict their occurrence. The functional and adaptive aspects of these results are discussed in the present article.  相似文献   
293.
294.
Theory and research on social support have paid little attention to the existence of important macrosocial variables determining level and content of social relationships. This study examines variations in social integration as a function of social class and residential area characteristics. Results for 234 subjects living in high and low risk neighbourhoods indicated that differences between higher and lower social class groups follow different patterns in different residential areas. Also, same social class position appeared to have different significance as a function of residential area characteristics. The levels of three social integration measures—community integration and satisfaction, community association and participation, and contribution in community organizations—were significantly higher for lower class in low risk neighbourhoods than in high risk ones. However, significant differences were found in only one measure for higher social class groups, with higher levels of community association and participation in high risk neighbourhoods than in low risk ones. The discussion examines a ‘social impoverishment’ hypothesis for high risk environments, and proposes possible protective factors for higher status residents. Relations between formal and informal sources of support, and implications for social intervention strategies are also considered.  相似文献   
295.
The DOI Kit is a four-version instrument (Junior Self and Other-Report, and Adult Self-and Other-Report) developed in Spain to measure ‘Dimensions of Interpersonal Orientation’ (Spanish: ‘Dimensiones de Orientación Interpersonal’ or DOI), which are defined as prevalent postures in interpersonal behaviour. The DOI Kit has six first-level scales that collapse into two broad oblique dimensions: Prosocial versus Antisocial Behaviour, and Sociability versus Unsociability.The aim of this article is to find out whether the first- and second-level structure of the Spanish DOI Kit can also be applied to data gathered in Chile and in Germany. A total of eight groups of data were studied. In order to find the best common structure for Spanish, Chilean, and German samples, Simultaneous Component Analysis (SCA) was applied. SCA shows an excellent replication of the original DOI Kit structure. This is also found when separate factor analyses (varimax and oblimin rotations) are performed.  相似文献   
296.
The purpose of this study was to examine the effects of focus of attention cues on movement coordination and coordination variability in the lower extremity. Twenty participants performed the standing long jump under both internal and external focus of attention conditions. A modified vector coding technique was used to evaluate the influence of attentional focus cues on lower extremity coordination patterns and coordination variability during the jumps. Participants jumped significantly further under an external focus of attention condition compared with an internal focus of attention condition (p = .035, effect size = .29). Focus of attention also influenced coordination between the ankle and knee, F(6, 19) = 2.87, p = .012, effect size = .388, with participants primarily using their knees under the internal focus of attention, and using both their ankles and knees under the external focus of attention. Attentional focus cues did not influence ankle-knee, F(1, 19) = 0.02, p = .98, effect size = .02, or hip-knee, F(1, 19) = 5.00, p = .49, effect size = .16, coordination variability. Results suggest that while attentional focus may not directly influence movement coordination condition, there is still a change in movement strategy resulting in greater jump distances following an external focus of attention.  相似文献   
297.
A notorious objection to robust virtue epistemology—the view that an agent knows a proposition if and only if her cognitive success is because of her intellectual virtues—is that it fails to eliminate knowledge-undermining luck. Modest virtue epistemologists agree with robust virtue epistemologists that if someone knows, then her cognitive success must be because of her intellectual virtues, but they think that more is needed for knowledge. More specifically, they introduce independently motivated modal anti-luck principles in their accounts to amend the problem of eliminating luck—this makes their views instances of impure virtue epistemology. The aim of the paper is to argue, firstly, that such a move lacks adequate motivation; secondly, that the resulting impure accounts equally fail to handle knowledge-undermining luck. On a more positive note, these results bolster a more orthodox virtue-theoretic approach to knowledge that assigns a fundamental explanatory role to the notion of ability. In this sense, the paper also sketches an account of ability and a corresponding account of knowledge that explains how success from ability (of the right kind) is incompatible with success from luck.  相似文献   
298.
This paper argues the relevance of analysing the origins of contextual effects to explain subjective well-being (SWB). Using the 2012 European Social Survey, the study applies social capital indicators to distinguish between-context and between-individual heterogeneity in three multilevel models of happiness and life satisfaction. Five indicators of social capital at individual and regional level are used to measure the trust, networks and norms dimensions of social capital. Random intercept and random slope hierarchical models are used to control for unexplained regional variability. The possibility of aggregated subjective perceptions conditioning, or interacting with, the effects of individual perceptions is also examined. The results show that the regional means of the social capital indicators are useful in explaining not only average levels of SWB (between-context heterogeneity) but also differences in the importance individuals attribute to their social capital (between-individual heterogeneity). The paper also proposes a research agenda to expand the frontier on contextual effects in the new science of well-being.  相似文献   
299.
300.
A number of training interventions have been designed to improve executive functions and inhibitory control (IC) across the lifespan. Surprisingly, no study has investigated the structural neuroplasticity induced by IC training from childhood to late adolescence, a developmental period characterized by IC efficiency improvement and protracted maturation of prefrontal cortex (PFC) subregions involved in IC. The aim of the present study was to investigate the behavioral and structural changes induced by a 5‐week computerized and adaptive IC training in school‐aged children (10‐year‐olds) and in adolescents (16‐year‐olds). Sixty‐four children and 59 adolescents were randomly assigned to an IC (i.e. Color‐Word Stroop and Stop‐Signal tasks) or an active control (AC) (knowledge‐ and vocabulary‐based tasks) training group. In the pre‐ and posttraining sessions, participants performed the Color‐Word Stroop and Stop‐signal tasks, and an anatomical resonance imaging (MRI) was acquired for each of them. Children's IC efficiency improved from the pre‐ to the posttraining session in boys but not in girls. In adolescents, IC efficiency did not improve after IC training. Similar to the neuroplastic mechanisms observed during brain maturation, we observed IC training‐related changes in cortical thickness and cortical surface area in several PFC subregions (e.g. the pars opercularis, triangularis, and orbitalis of the inferior frontal gyri) that were age‐ and gender‐specific. Because no correction for multiple comparisons was applied, the results of our study provide only preliminary evidence of the complex structural neuroplastic mechanisms at the root of behavioral changes in IC efficiency from pre‐ to posttraining in school‐aged children and adolescents.  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