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   15650篇
  免费   716篇
  国内免费   8篇
  2023年   98篇
  2022年   93篇
  2021年   182篇
  2020年   289篇
  2019年   359篇
  2018年   493篇
  2017年   484篇
  2016年   533篇
  2015年   355篇
  2014年   465篇
  2013年   1722篇
  2012年   811篇
  2011年   801篇
  2010年   531篇
  2009年   567篇
  2008年   801篇
  2007年   778篇
  2006年   661篇
  2005年   581篇
  2004年   613篇
  2003年   571篇
  2002年   542篇
  2001年   228篇
  2000年   237篇
  1999年   227篇
  1998年   236篇
  1997年   194篇
  1996年   143篇
  1995年   179篇
  1994年   162篇
  1993年   154篇
  1992年   136篇
  1991年   121篇
  1990年   116篇
  1989年   115篇
  1988年   114篇
  1987年   114篇
  1986年   89篇
  1985年   110篇
  1984年   123篇
  1983年   104篇
  1982年   114篇
  1981年   121篇
  1980年   109篇
  1979年   108篇
  1978年   113篇
  1977年   91篇
  1976年   95篇
  1975年   65篇
  1974年   78篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
This study replicates and extends prior studies of the dimensionality, convergent, and external validity of African Self-Consciousness Scale scores with appropriate exploratory factor analysis methods and a large gender balanced sample (N = 348). Viable one- and two-factor solutions were cross-validated. Both first factors overlapped significantly and were labeled "Embracing African Heritage." The second subscale of the two-factor solution was labeled "Refusal to Deny African Heritage." Only the structural validity of the first factor of the two-factor solution was fully consistent with prior findings. Partial evidence of convergent validity was found for all factors, and only the second factor of the two-factor solution received external validity support. Implications for usage of the African Self-Consciousness Scale and recommendations for further investigation are discussed.  相似文献   
992.
With increasing popularity, growth curve modeling is more and more often considered as the 1st choice for analyzing longitudinal data. Although the growth curve approach is often a good choice, other modeling strategies may more directly answer questions of interest. It is common to see researchers fit growth curve models without considering alterative modeling strategies. In this article we compare 3 approaches for analyzing longitudinal data: repeated measures analysis of variance, covariance pattern models, and growth curve models. As all are members of the general linear mixed model family, they represent somewhat different assumptions about the way individuals change. These assumptions result in different patterns of covariation among the residuals around the fixed effects. In this article, we first indicate the kinds of data that are appropriately modeled by each and use real data examples to demonstrate possible problems associated with the blanket selection of the growth curve model. We then present a simulation that indicates the utility of Akaike information criterion and Bayesian information criterion in the selection of a proper residual covariance structure. The results cast doubt on the popular practice of automatically using growth curve modeling for longitudinal data without comparing the fit of different models. Finally, we provide some practical advice for assessing mean changes in the presence of correlated data.  相似文献   
993.
Objective: Preclinical models, receptor localization, and genetic linkage data support the role of D4 receptors in the etiology of ADHD. This proof-of-concept study was designed to evaluate MK-0929, a selective D4 receptor antagonist as treatment for adult ADHD. Method: A randomized, double-blind, placebo-controlled, crossover study was conducted in adults with primary ADHD. The primary end point was changed from baseline in total score on the Adult ADHD Investigator Symptom Rating Scale following a 4-week treatment regimen. Additional measures included Clinical Global Impression-Severity Scale, Hospital Anxiety and Depression Scale, and Brown Attention Deficit Disorder Scale and D4 genotype analysis. Results: No statistically significant treatment differences were found between MK-0929 and placebo in any of the primary or secondary assessments. Conclusion: Results from this study suggest that blockade of the D4 receptor alone is not efficacious in the treatment of adult ADHD.  相似文献   
994.
Moral Machines?     
Wendell Wallach and Colin Allen??s Moral Machines: Teaching Robots Right From Wrong (Oxford University Press, 2009) explores efforts to develop machines that, not only can be employed for good or bad ends, but which themselves can be held morally accountable for what they do??artificial moral agents (AMAs). This essay is a critical response to Wallach and Allen??s conjectures. Although Wallach and Allen do not suggest that we are close to being able to create full-fledged AMAs, they do talk seriously about making incremental progress in the direction of creating them (even if we never fully succeed). However, there are important questions about the moral development of AMAs that Moral Machines does not address. Given the responsibilities entrusted to human moral agents, we take questions about their moral development very seriously. In the case of children, the hope is that eventually they will develop into full-fledged moral agents. How might we expect this to go with less than fully formed AMAs? Will there be a comparable story of moral development and moral education that we can tell?  相似文献   
995.
Theoretical and empirical research investigating victimization and offending has largely been either ‘victim-focused’ or ‘offender-focused.’ This approach ignores the potential theoretical and empirical overlap that may exist among victims and offenders, otherwise referred to as ‘victim-offenders.’ This paper provides a comprehensive review of the research that has examined the relationship between victimization and offending. The review identified 37 studies, spanning over five decades (1958-2011), that have assessed the victim-offender overlap. The empirical evidence gleaned from these studies with regard to the victim-offender overlap is robust as 31 studies found considerable support for the overlap and six additional studies found mixed/limited support. The evidence is also remarkably consistent across a diversity of analytical and statistical techniques and across historical, contemporary, cross-cultural, and international assessments of the victim-offender overlap. In addition, this overlap is identifiable among dating/intimate partners and mental health populations. Conclusions and directions for future research are also discussed.  相似文献   
996.
This review considers the impact of deliberate emotion regulation on aggression, by integrating findings from recent emotion regulation research with a contemporary model of aggressive behavior, the General Aggression Model. First, it considers how individuals who under-regulate anger and other emotions may be more likely to behave aggressively in an attempt to repair, terminate, or avoid uncomfortable emotional states. Second, it explores how over-regulation of emotion may lead to aggressive behavior by increasing negative affect, reducing inhibitions against aggression, compromising decision making processes, diminishing social networks, increasing physiological arousal and hindering the resolution of difficult situations. Finally, it reviews three skills thought to underlie deliberate emotion regulation: emotional awareness, emotional acceptance and proficiency in a variety of emotion regulation strategies. Treatment encompassing all of these skills may improve an individual's ability to regulate difficult emotion states more adaptively and thereby lessen aggressive behavior.  相似文献   
997.
Based on anticipatory looking and reactions to violations of expected events, infants have been credited with 'theory of mind' (ToM) knowledge that a person's search behaviour for an object will be guided by true or false beliefs about the object's location. However, little is known about the preconditions for looking patterns consistent with belief attribution in infants. In this study, we compared the performance of 17- to 26-month-olds on anticipatory looking in ToM tasks. The infants were either hearing or were deaf from hearing families and thus delayed in communicative experience gained from access to language and conversational input. Hearing infants significantly outperformed their deaf counterparts in anticipating the search actions of a cartoon character that held a false belief about a target-object location. By contrast, the performance of the two groups in a true belief condition did not differ significantly. These findings suggest for the first time that access to language and conversational input contributes to early ToM reasoning.  相似文献   
998.
Some children’s social activities are structured by joint goals. In previous research, the criterion used to determine this was relatively weak: if the partner stopped interacting, did the child attempt to re‐engage her? But re‐engagement attempts could easily result from the child simply realizing that she needs the partner to reach her own goal in the activity (social tool explanation). In two experiments, 21‐ and 27‐month‐old children interacted with an adult in games in which they either did or did not physically need the partner to reach a concrete goal. Moreover, when the partner stopped interacting, she did so because she was either unwilling to continue (breaking off from the joint goal) or unable to continue (presumably still maintaining the joint goal). Children of both age groups encouraged the recalcitrant partner equally often whether she was or was not physically needed for goal attainment. In addition, they did so more often when the partner was unable to continue than when she was unwilling to continue. These findings suggest that young children do not just view their collaborative partners as mindless social tools, but rather as intentional, cooperative agents with whom they must coordinate intentional states.  相似文献   
999.
Despite its importance in the development of children’s skills of social cognition and communication, very little is known about the ontogenetic origins of the pointing gesture. We report a training study in which mothers gave children one month of extra daily experience with pointing as compared with a control group who had extra experience with musical activities. One hundred and two infants of 9, 10, or 11 months of age were seen at the beginning, middle, and end of this one‐month period and tested for declarative pointing and gaze following. Infants’ability to point with the index finger at the end of the study was not affected by the training but was instead predicted by infants’ prior ability to follow the gaze direction of an adult. The frequency with which infants pointed indexically was also affected by infant gaze following ability and, in addition, by maternal pointing frequency in free play, but not by training. In contrast, infants’ ability to monitor their partner’s gaze when pointing, and the frequency with which they did so, was affected by both training and maternal pointing frequency in free play. These results suggest that prior social cognitive advances, rather than adult socialization of pointing per se, determine the developmental onset of indexical pointing, but socialization processes such as imitation and adult shaping subsequently affect both infants’ ability to monitor their interlocutor’s gaze while they point and how frequently infants choose to point.  相似文献   
1000.
The relationship of motor proficiency with emotional/behavioural disturbance, autistic symptoms and communication disturbance was investigated in children diagnosed with autism and Asperger's disorder (AD). The Movement Assessment Battery for Children was used as a measure of motor impairment, and the Developmental Behavioural Checklist was used as a measure of emotional/behavioural disturbance in the following groups: AD (n?=?22), high functioning autism (HFA) (n?=?23), LFA (n?=?8) and typically developing children (n?=?20). The HFA group had more difficulty with motor items, such as ball skills and balance, than did the AD group. There were significant positive correlations between impairments in motor proficiency (in particular ball skills and balance) and emotional/behavioural disturbance, autistic symptoms and communication disturbance. These findings are consistent with the hypothesis that there are qualitative and quantitative differences in the motor profile between autism and AD. In addition, the association between motor proficiency impairment and emotional/behavioural disturbance in autism and AD emphasizes the importance for screening of co-occurring emotional/behavioural symptoms in individuals with motor difficulties. These findings have implications for the potential use of adjunct motor measures in the diagnosis and definition of autism spectrum disorders.  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