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   830篇
  免费   68篇
  国内免费   1篇
  899篇
  2023年   20篇
  2022年   4篇
  2021年   14篇
  2020年   35篇
  2019年   40篇
  2018年   51篇
  2017年   49篇
  2016年   49篇
  2015年   38篇
  2014年   42篇
  2013年   114篇
  2012年   54篇
  2011年   48篇
  2010年   27篇
  2009年   26篇
  2008年   41篇
  2007年   34篇
  2006年   28篇
  2005年   22篇
  2004年   23篇
  2003年   19篇
  2002年   15篇
  2001年   9篇
  2000年   6篇
  1999年   4篇
  1998年   9篇
  1997年   6篇
  1996年   5篇
  1995年   4篇
  1994年   5篇
  1993年   5篇
  1992年   4篇
  1991年   4篇
  1990年   3篇
  1989年   5篇
  1988年   3篇
  1987年   5篇
  1985年   3篇
  1984年   5篇
  1983年   2篇
  1982年   6篇
  1981年   1篇
  1980年   1篇
  1979年   2篇
  1977年   2篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1963年   1篇
  1951年   1篇
排序方式: 共有899条查询结果,搜索用时 9 毫秒
211.
Conditioned behavior as observed during classical conditioning in a group of identically treated animals provides insights into the physiological process of learning and memory formation. However, several studies in vertebrates found a remarkable difference between the group-average behavioral performance and the behavioral characteristics of individual animals. Here, we analyzed a large number of data (1640 animals) on olfactory conditioning in the honeybee (Apis mellifera). The data acquired during absolute and differential classical conditioning differed with respect to the number of conditioning trials, the conditioned odors, the intertrial intervals, and the time of retention tests. We further investigated data in which animals were tested for spontaneous recovery from extinction. In all data sets we found that the gradually increasing group-average learning curve did not adequately represent the behavior of individual animals. Individual behavior was characterized by a rapid and stable acquisition of the conditioned response (CR), as well as by a rapid and stable cessation of the CR following unrewarded stimuli. In addition, we present and evaluate different model hypotheses on how honeybees form associations during classical conditioning by implementing a gradual learning process on the one hand and an all-or-none learning process on the other hand. In summary, our findings advise that individual behavior should be recognized as a meaningful predictor for the internal state of a honeybee--irrespective of the group-average behavioral performance.  相似文献   
212.

Objective

The purpose of this study was to synthesize findings from motivational climate interventions employing [Ames, 1992a] and [Ames, 1992b] and [Epstein, 1988] and [Epstein, 1989] TARGET framework within school-based physical education contexts.

Design

The present study employed a quantitative research synthesis design. Meta-analysis uses empirical studies to summarize past research by drawing overall conclusions from separate investigations. This research design highlights important and unsolved issues related to motivational climate interventions within physical education.

Methods

Standard meta-analytic procedures incorporating inclusion and exclusion criteria, literature search, coding procedures, and statistical methods were used to identify and synthesize 22 studies with 24 independent samples. Cohen’s (1988) criteria for effect sizes were used to interpret and evaluate results.

Results

There was an overall small positive treatment effect (g = 0.103) for groups exposed to mastery motivational climates. Outcome analyses identified the most consistent and largest overall treatment effects for behavioral outcomes (g = 0.39–0.49) followed by affective outcomes (g = −0.27 to 0.59) and cognitive outcomes (g = −0.25 to 0.32). Moderator analyses were directed by study heterogeneity and identified several trends in intervention features and study features with the most substantial trend for participant features as elementary students had the largest overall treatment effect (g = 0.41).

Conclusions

Outcome and moderator analyses identified several trends in methodological features, participant features, and study features that should be addressed in future physical education motivational climate interventions.  相似文献   
213.
Our primary focus is on analysis of the concept of voluntariness, with a secondary focus on the implications of our analysis for the concept and the requirements of voluntary informed consent. We propose that two necessary and jointly sufficient conditions must be satisfied for an action to be voluntary: intentionality, and substantial freedom from controlling influences. We reject authenticity as a necessary condition of voluntary action, and we note that constraining situations may or may not undermine voluntariness, depending on the circumstances and the psychological capacities of agents. We compare and evaluate several accounts of voluntariness and argue that our view, unlike other treatments in bioethics, is not a value-laden theory. We also discuss the empirical assessment of individuals' perceptions of the degrees of noncontrol and self-control. We propose use of a particular Decision Making Control Instrument. Empirical research using this instrument can provide data that will help establish appropriate policies and procedures for obtaining voluntary consent to research.  相似文献   
214.
Abstract

Research on the performance of total congenital blind subjects in imagery tasks is of particular interest because it helps to evaluate the consequences of their lack of visual experience. The present paper examines some points which remained unclear in the preceding research on the effects of imagery instructions on the recall of blind subjects. In Experiment 1 it is shown that, in a free recall task of unrelated nouns, the blind may take advantage of imagery instructions, independently of the particular requirement to form either common or bizarre images. In Experiment 2 the multiple image processing deficit of the blind found by De Beni and Cornoldi (1988) was again observed, but the effect was not found when the same quantity of material had to be processed verbally. Results are interpreted as showing that, although the blind may follow imagery instructions, their visual handicap creates specific difficulties in creating interactive images involving several items at the same time.  相似文献   
215.
216.
This study examined how urbanisation may modify adolescents' values and activities concerning family obligation by surveying 572 adolescents (Mage = 15.75, SD = .73) in rural and urban Vietnam. Compared with their rural peers, urban adolescents reported a stronger sense of family obligation but spent less time actually engaging in family assistance, findings that were partly explained by urban households' less financial hardship and higher parental education levels. As expected, stronger family obligation values were associated with greater family assistance activities across rural and urban Vietnam. However, stronger family obligation values were associated with more study hours only in urban Vietnam, indicating that urbanisation may broaden the meaning of family obligation to encompass the academic domain. Additionally, weaker family obligation values were associated with more employment hours only in rural Vietnam, suggesting that rural adolescents with little attachment to the traditional value of family obligation may pursue autonomy through employment outside the home. In traditionally familistic societies undergoing urbanisation, family obligation may take on different meaning depending on adolescents' ecological settings that construct cultural values and behavioural norms.  相似文献   
217.
The overrepresentation of individuals with mental illness in the criminal/legal system is well documented. While professional associations urge diversion towards treatment, little is known about the practices these institutions use to identify this population. One understudied space in the criminal/legal continuum is jails. This exploratory study compares two types of mental health identification at jail booking to assess jail‐ and community‐based service outcomes by identification type (N = 2956): (a) staff observation and (b) a standardized screening instrument. Individuals identified through staff observation were significantly more likely to receive jail‐ and community‐based services, even though current symptomology and substance misuse were both significantly higher for individuals identified only by the screening instrument. These findings point to the importance of jails in providing stabilizing services during incarceration, but further, show the impact that identification practices have on individuals as they transition to the community. Community context showed varied rates of jail staff observations of mental illness, showing greater risks for individuals in rural communities. Implications include a need for system‐level changes by instituting evidence‐based identification practices in jails, and improving professional collaboration practices between mental health and criminal/legal practitioners as individuals enter and exit jails.  相似文献   
218.
Healthcare providers assume that there are minimal risks and potential psychosocial benefits for children who undergo a bone marrow harvest for the benefit of their critically ill siblings. Ethical justifications for the use of children as donors rely on there being minimal risks since donors receive no direct medical benefits from the intervention. There is little empirical research regarding psychosocial consequences. This article reviews relevant research in three contexts: a) psychosocial outcomes for adults and children who donate tissue and organs; b) psychosocial impacts on a sibling of a pediatric cancer patient; and c) children's decision-making regarding medical decisions. The relevant research literature supports the belief that the psychosocial impact on a child bone marrow donor will be influenced by the survival of the recipient, the age of the donor, and the donor's participation in the decision to donate. In order to empirically validate the actual psychosocial risks (and benefits) for donors, it is argued that direct research is needed so that a donor's well-being can be protected.  相似文献   
219.
220.
Background and objectives: Anxiety disorders are the most common mental health problems during childhood and adolescence. This study examined the course of anxiety symptoms in early adolescents from the general population over three phases.

Design: Prospective cohort study.

Methods: Two hundred and forty-two participants (mean-age of 13.52) from a baseline sample of 1514 (mean-age of 10.23) were followed up three times. Of the 1514 children, those with emotional risk and controls without risk constituted the second-phase sample (n?=?562; mean-age of 11.25). The Screen for Child Anxiety Related Emotional Disorders-SCARED was administered in all three phases.

Results: Fifty-six percent and 32% of respondents showed total scores above the SCARED cutoff point at one and three years follow-up, respectively. Eight percent showed fluctuating symptoms. Fifty-five percent of respondents showed high scores for any subtype of anxiety over three years. Social phobia and generalized anxiety symptoms were the most prevalent and persistent. Participants with persistent separation anxiety showed the highest co-occurrence with symptoms of other psychopathological disorders. Participants with persistent anxiety showed lower academic performance. Being male was a protective factor against persistence.

Conclusions: The data support anxiety maintenance during early adolescence. Early adolescence is a critical period which may involve other serious academic, social, and family problems.  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