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   4956篇
  免费   2324篇
  国内免费   168篇
  2024年   2篇
  2023年   31篇
  2022年   31篇
  2021年   162篇
  2020年   210篇
  2019年   640篇
  2018年   552篇
  2017年   660篇
  2016年   636篇
  2015年   527篇
  2014年   462篇
  2013年   768篇
  2012年   325篇
  2011年   298篇
  2010年   221篇
  2009年   226篇
  2008年   183篇
  2007年   233篇
  2006年   213篇
  2005年   197篇
  2004年   147篇
  2003年   162篇
  2002年   135篇
  2001年   127篇
  2000年   87篇
  1999年   67篇
  1998年   34篇
  1997年   18篇
  1996年   17篇
  1995年   16篇
  1994年   10篇
  1993年   14篇
  1992年   8篇
  1991年   5篇
  1990年   6篇
  1989年   5篇
  1988年   4篇
  1987年   1篇
  1985年   1篇
  1981年   2篇
  1980年   1篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
排序方式: 共有7448条查询结果,搜索用时 15 毫秒
111.
Covert food stealing is common among individuals with Prader-Willi syndrome. We found that verbal reprimands, delivered contingent upon eating prohibited foods, were sufficient to decrease the food stealing of a girl with Prader-Willi syndrome. Warning stimuli were then used to help her discriminate between permitted and prohibited foods during sessions in which food stealing was not directly observed. This procedure resulted in decreases in food stealing from containers labeled with the warning stimuli.  相似文献   
112.
Children with attention deficit hyperactivity disorder (ADHD) are often treated with central nervous system stimulants, making the evaluation of medication effects an important topic for applied behavior analysts. Because assessment protocols emphasize informant reports and direct observations of child behavior, little is known about the extent to which children themselves can accurately report medication effects. Double-blind placebo-controlled procedures were used to examine whether 6 children with ADHD could recognize the effects of their medication. The children were given math worksheets to complete for 15 min during each of 14 sessions while on medication and placebo. Children completed a self-evaluation form at the end of each session, and ratings were compared to observed behavior and academic performance. Results indicated that 3 children were able to accurately report their medication status at levels greater than chance, whereas the accuracy of reports by all children was related to dosage level, differences in behavior, and the presence of adverse effects. The implications of these results for placebo-controlled research, self-monitoring of dosage levels, and accuracy training are discussed.  相似文献   
113.
Four rats were studied with variants of a progressive-ratio schedule with a step size of 6 in which different terminal components followed completion of the 20th ratio: (a) a reversal of the progression, (b) a fixed-ratio 6 schedule, or (c) extinction. Responding in the progressive-ratio components of these schedules was compared to performances under conventional progressive-ratio baselines. Under baseline conditions, postreinforcement pauses increased exponentially as a function of increasing ratio size, whereas running rates showed modest declines. The procedure of linking the progressive-ratio schedule to the reversed progression or to the fixed-ratio component resulted in decreased pausing. Linking the progressive-ratio schedule to the extinction component had the opposite effect, that of producing weakened progressive-ratio performances as evidenced by increased pausing. Subjects whose responses were reinforced on half of the ratios also showed exponential increases; however, pauses were substantially shorter following ratios on which the reinforcer was omitted. The results suggested that progressive-ratio pausing reflects the influence of remote as well as local contingencies.  相似文献   
114.
Three experiments were conducted to examine pigeons' postponement of signaled extinction periods (timeouts) from a schedule of food reinforcement when such responding neither decreased overall timeout frequency nor increased the overall frequency of food reinforcement. A discrete-trial procedure was used in which a response during the first 5 s of a trial postponed an otherwise immediate 60-s timeout to a later part of that same trial but had no effect on whether the timeout occurred. During time-in periods, responses on a second key produced food according to a random-interval 20-s schedule. In Experiment 1, the response-timeout interval was 45 s under postponement conditions and 0 s under extinction conditions (responses were ineffective in postponing timeouts). The percentage of trials with a response was consistently high when the timeout-postponement contingency was in effect and decreased to low levels when it was discontinued under extinction conditions. In Experiment 2, the response-timeout interval was also 45 s but postponement responses increased the duration of the timeout, which varied from 60 s to 105 s across conditions. Postponement responding was maintained, generally at high levels, at all timeout durations, despite sometimes large decreases in the overall frequency of food reinforcement. In Experiment 3, timeout duration was held constant at 60 s while the response-timeout interval was varied systematically across conditions from 0 s to 45 s. Postponement responding was maintained under all conditions in which the response-timeout interval exceeded 0 s (the timeout interval in the absence of a response). In some conditions of Experiment 3, which were designed to control for the immediacy of food reinforcement and food-correlated (time-in) stimuli, responding postponed timeout but the timeout was delayed whether a response occurred or not. Responding was maintained for 2 of 3 subjects, suggesting that behavior was negatively reinforced by timeout postponement rather than positively reinforced by the more immediate presentation of food or food-correlated (time-in) stimuli.  相似文献   
115.
Out of the many aspects of posttraumatic adaptation the role of self-process is emphasized, where self is conceptualized as the representation of social interaction: Not only the messages conveyed by others, but also a person's inner response to that messages, forms ongoing self-processes. Traumatic experiences lead to distorted self-processes, to a great extent due to posttraumatic inner dialogues. Therapeutic implications and experiences from Bosnia are discussed, where this model has been applied.  相似文献   
116.
Professional autonomy is often described as a claim of professionalsthat has to serve primarily their own interests. However, it can also beseen as an element of a professional ideal that can function as astandard for professional, i.e. medical practice. This normativeunderstanding of the medical profession and professional autonomy facesthree threats today. 1) Internal erosion of professional autonomy due toa lack of internal quality control by the medical profession; 2)the increasing upward pressure on health care expenses that calls for ahealth care policy that could imply limitations for the professionalautonomy of physicians; 3) a distorted understanding of theprofession as being based on a formal type of knowledge and relatedtechnology, in which other normative dimensions of medical practice areneglected and which frustrates meaningful communication betweenphysicians and patients. To answer these threats a normative structureanalysis of medical practice is presented, that indicates whichprinciples and norms are constitutive for medical practice. It isconcluded that professional autonomy, normatively understood, should bemaintained to avoid the lure of the technological imperative and toprotect patients against third parties' pressure to undertreatment.However, this professional autonomy can only be maintained if members ofthe profession subject their activities and decisions to a criticalevaluation by other members of the profession and by patients and ifthey continue to critically reflect on the values that regulate today'smedicine.  相似文献   
117.
James Joyce's argument with himself about where he should practice his art and with what literary tradition he should identify—Irish, British, or European—is represented by several of the characters and episodes in his short story The Dead.In the main character, Gabriel Conroy, Joyce represented the conflicts that he himself experienced. But in many of the minor characters Joyce also reflected parts of his own wishes and fears.In this story, Joyce rejects the possibilities of artistic identification with Ireland and England, and, in the dynamics of the tale, arrives at the understanding that to fulfill his artistic aspirations, he must make an identification with the great European tradition, and also live in Europe; if he stays in Ireland or attempts to be an English author, he will be, as he portrays Gabriel to be, paralyzed, imitative, and a failure as an artist. Joyce himself took the decisive path that Gabriel could not choose.  相似文献   
118.
Ruffman T  Slade L  Redman J 《Cognition》2005,97(2):B35-B43
Infants aged 3-5 months (mean of approximately 4 months) were given a novel anticipatory looking task to test object permanence understanding. They were trained to expect an experimenter to retrieve an object from behind a transparent screen upon hearing a cue ("Doors up, here comes the hand"). The experimenter then hid the object behind one of two opaque screens and after either 2 or 8s gave the "doors up" cue. Infants looked to the correct location after the two-second delay, but not after the eight-second delay. This indicates a brief memory that the object is present behind the occluder. The study provides converging evidence that infants grasp object permanence by a young age. The novel anticipatory looking paradigm helps rule out counter-explanations applied to violation-of-expectation tasks.  相似文献   
119.
Botvinick MM 《Cognition》2005,97(2):135-151
Knowledge concerning domain-specific regularities in sequential structure has long been known to affect recall for serial order. However, very little work has been done toward specifying the exact role such knowledge plays. The present article proposes a theory of serial recall in structured domains, based on Bayesian decision theory and a set of representational assumptions proceeding from recent computational and neurophysiologic research. The theory suggests that the accuracy with which a target sequence will be recalled is influenced by two interacting factors: (1) the 'goodness' of the sequence, i.e. its fit with the sequencing constraints that characterize its source domain, and (2) the sequence's neighborhood relations, i.e. the degree to which it resembles other sequences in the source domain. A specific prediction of the theory is that recall will be relatively poor for target lists with high-goodness near neighbors (the good neighbor effect). This prediction was tested and confirmed in an experiment evaluating recall for sequences based on an artificial grammar.  相似文献   
120.
Brief multiple-stimulus-without-replacement (MSWO) preference assessments were conducted with 3 adolescent boys with emotional-behavioral disorders in the context of their public school educational program. The reinforcing effects of stimuli identified as high, medium, and low preference were then evaluated using an alternating treatments design in which, following an initial baseline, stimuli were delivered contingent on on-task behavior. High-preference stimuli produced the highest percentages of on-task behavior for all 3 participants.  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