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   2301篇
  免费   87篇
  2388篇
  2021年   23篇
  2020年   22篇
  2019年   32篇
  2018年   46篇
  2017年   38篇
  2016年   66篇
  2015年   46篇
  2014年   58篇
  2013年   277篇
  2012年   82篇
  2011年   104篇
  2010年   69篇
  2009年   58篇
  2008年   96篇
  2007年   87篇
  2006年   83篇
  2005年   86篇
  2004年   65篇
  2003年   73篇
  2002年   65篇
  2001年   32篇
  2000年   38篇
  1999年   33篇
  1998年   38篇
  1997年   33篇
  1996年   26篇
  1995年   27篇
  1994年   35篇
  1993年   21篇
  1992年   31篇
  1991年   23篇
  1990年   24篇
  1989年   21篇
  1988年   23篇
  1987年   19篇
  1986年   21篇
  1985年   27篇
  1984年   28篇
  1983年   23篇
  1982年   33篇
  1981年   30篇
  1980年   26篇
  1979年   30篇
  1978年   19篇
  1977年   20篇
  1976年   16篇
  1975年   15篇
  1974年   15篇
  1973年   16篇
  1966年   14篇
排序方式: 共有2388条查询结果,搜索用时 8 毫秒
131.
Zusammenfassung. Das hier vorgestellte Modell lernt graduell, Planungsaufgaben aus der Klasse der Maschinenbelegungsprobleme (job-shop-scheduling problems) zu lösen. Mit Hilfe des Chunking-Mechanismus von Soar wird episodisches Wissen über die Belegungsreihenfolge von Aufträgen auf Maschinen memoriert. Bei der Entwicklung des Modells wurden zahlreiche qualitative (z. B. Transfereffekte) und quantitative Befunde (z. B. Bearbeitungszeiten) aus einer früheren empirischen Untersuchung berücksichtigt. In einer Validierungsstudie wurden dieselben Aufgaben von 14 Probanden und dem Modell bearbeitet. Die Passung von Simulationsdaten und empirischen Ergebnissen fiel insgesamt gut aus. Allerdings löst das Modell die Aufgaben schneller und zeigt auch einen etwas besseren Lernverlauf als die Probanden. Das Modell liefert eine Erklärung für das Rauschen, das typischerweise bei Bearbeitungszeiten zu beobachten ist: es handelt sich um erworbenes Wissen, das mehr oder weniger gut und auch unterschiedlich häufig auf neue Situationen übertragen wird. Der Lernverlauf der Probanden entspricht nur für aggregierte Daten einer Potenzfunktion (power law). Der vorgestellte Mechanismus zeigt, wie ein symbolisches Modell der Informationsverarbeitung graduelle Verhaltensänderungen generiert und wie der offensichtliche Erwerb allgemeiner Prozeduren ohne explizites Lernen von deklarativen Regeln erfolgen kann. Es wird nahegelegt, daß es sich hier um die Modellierung einer Form impliziten Lernens handelt. Summary. The model presented here gradually learns how to perform a job-shop scheduling task. It uses Soar's chunking mechanism to acquire episodic memories about the order to schedule jobs. The model was based on many qualitative (e.g., transfer effects) and quantitative (e.g., solution time) regularities found in previously collected data. The model was tested with new data where scheduling tasks were given to the model and to 14 subjects. The model generally fit these data with the restrictions that the model performs the task (in simulated time) faster than the subjects, and its performance improves somewhat more quickly than the subjects' performance. The model provides an explanation of the noise typically found in problem solving times - it is the result of learning actual pieces of knowledge that transfer more or less to new situations but rarely by an average amount. Only when the data are averaged (i.e., over subjects) does the smooth power law appear. This mechanism demonstrates how symbolic models can exhibit a gradual change in behavior and how the apparent acquisition of general procedures can be performed without resorting to explicit declarative rule generation. We suggest that this may represent a type of implicit learning.  相似文献   
132.
133.
The Comprehensive Services Act for At Risk Youth and Families of Virginia (CSA), is a service, funding, and organizational reform initiative designed to improve the provision of child centered and family focused services within a community setting. We conducted this study in order to assess the feasibility of applying utilization management principles to the CSA in order to improve the appropriateness, quality, and cost effectiveness of this service delivery system. Data were gathered through focus groups, surveys, clinical profiling, and analysis of costs, and service utilization. While overall program costs increased since inception of the program, the costs per child served rose less than the rate of inflation. CSA appeared to be serving children with a high degree of emotional and behavioral difficulties. There was considerable variation among localities in placement patterns. A majority of survey and focus group respondents were willing to consider the application of utilization management principles to the CSA as long as decision making remained within localities. We concluded that there is a constructive role for utilization management approaches to improve the appropriateness and quality of services as well as enhancing efficiency in child mental health.  相似文献   
134.
A remote-controlled device was developed for injection of fluids and collection of blood samples from freely moving, socially housed animals via an indwelling catheter. Samples are collected at times chosen by the investigator, and the animal is not aware that sampling is occurring. This technique allows measurement of plasma catecholamines and other substances that fluctuate rapidly, are affected by psychosocial stimuli, and are altered by capture and other stressful activities that often accompany sample collection. Rapid retrieval of samples is facilitated by remote-controlled injection of an anesthetic. The device has been used to collect blood from dominant and subordinate male baboons before and during events such as chases and presentation of food treats. Heart rate and blood pressure were measured via radio telemetry, and behavior was recorded on videotapes. This technique allowed construction of multifaceted physiological profiles of social roles and behaviors.  相似文献   
135.
In two studies, we tested the relationship between non‐immigrant individuals' perceptions of deviant behavior carried out by Muslims and foreigners and discriminatory intentions towards these outgroups. Based on a longitudinal and a representative cross‐sectional sample, we showed that two different types of perceived deviant behavior (Study 1, Muslims' unwillingness to integrate; and Study 2, foreigners' hostility towards the non‐immigrant majority group) are related to increased intergroup threat, which in turn is related to increased intentions to show passive discrimination (i.e., avoidance) towards these outgroups. In line with theorizing about an increased sensitivity for threat in authoritarian individuals, the relationship between perceptions of deviant behavior and threat was especially strong among high authoritarian individuals. Theoretical and practical implications of our results are discussed.  相似文献   
136.
Individuals with agrammatic Broca's aphasia experience difficulty when processing reversible non‐canonical sentences. Different accounts have been proposed to explain this phenomenon. The Trace Deletion account (Grodzinsky, 1995, 2000, 2006) attributes this deficit to an impairment in syntactic representations, whereas others (e.g., Caplan, Waters, Dede, Michaud, & Reddy, 2007; Haarmann, Just, & Carpenter, 1997) propose that the underlying structural representations are unimpaired, but sentence comprehension is affected by processing deficits, such as slow lexical activation, reduction in memory resources, slowed processing and/or intermittent deficiency, among others. We test the claims of two processing accounts, slowed processing and intermittent deficiency, and two versions of the Trace Deletion Hypothesis (TDH), in a computational framework for sentence processing (Lewis & Vasishth, 2005) implemented in ACT‐R (Anderson, Byrne, Douglass, Lebiere, & Qin, 2004). The assumption of slowed processing is operationalized as slow procedural memory, so that each processing action is performed slower than normal, and intermittent deficiency as extra noise in the procedural memory, so that the parsing steps are more noisy than normal. We operationalize the TDH as an absence of trace information in the parse tree. To test the predictions of the models implementing these theories, we use the data from a German sentence—picture matching study reported in Hanne, Sekerina, Vasishth, Burchert, and De Bleser (2011). The data consist of offline (sentence‐picture matching accuracies and response times) and online (eye fixation proportions) measures. From among the models considered, the model assuming that both slowed processing and intermittent deficiency are present emerges as the best model of sentence processing difficulty in aphasia. The modeling of individual differences suggests that, if we assume that patients have both slowed processing and intermittent deficiency, they have them in differing degrees.  相似文献   
137.
My interest in the theory and art of psychoanalysis is traced to some of its sources—my childhood and expulsion from Germany in the late 1930s, my experience as a member of a discriminated-against minority, my nonacceptance as a psychologist by American psychoanalytic societies, my invitation to participate in the development of self psychology, and my fortuitous encounter with personal and professional friends who have contributed to the scope of my psychoanalytic endeavors (e.g., to my abiding interest in research and, in particular, the empirical studies of the early mother–infant dyad). I offer this account as evidence of the varied and creative opportunities that await psychoanalysts not outside but beyond the mainstream of American psychoanalysis.  相似文献   
138.
A set of three studies replicated and extended Abbey's (1982) research, indicating that men perceive less friendliness, but more sexuality than women when observing women's social interactions. Study 1 was based on 49 previously unacquainted male-female pairs who engaged in brief face-to-face discussions, and 48 males and 61 females who observed one of those discussions. Study 2 was based on videotaped exchanges between a male store manager and a female cashier, and Study 3 between a male professor and a female student; 75 males and 88 females participated in Study 2, while 98 males and 102 females participated in Study 3. In all three studies, the men saw less friendliness, but more sexiness in the woman's behavior than the women. These results support the idea that some of the less severe forms of sexual harassment in business and academic settings may be better understood eventually through research and theory development that considers these sex differences in social perceptions.  相似文献   
139.
Infertility is a major life stressor that affects approximately 10% of U.S. married couples. Infertile women and men have reported experiencing depression, helplessness, and marital strain. Given U.S. society's emphasis on women's role as mothers, it has been suggested that women's lives are more disrupted by infertility than those of men. This hypothesis was supported in a survey of 185 infertile couples and 90 presumed fertile couples. Infertile wives, as compared to their husbands, perceived their fertility problem as more stressful, felt more responsible for and in control of their infertility, and engaged in more problem-focused coping. Infertile husbands experienced more home life stress and lower home life performance than did their wives. These differences were not found for presumed fertile couples. Both infertile and presumed fertile wives experienced more depression, more sexual dissatisfaction, and lower self-esteem than did their husbands. Theoretical and counseling implications of these findings are discussed.  相似文献   
140.
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