全文获取类型
收费全文 | 2487篇 |
免费 | 147篇 |
国内免费 | 4篇 |
出版年
2023年 | 19篇 |
2021年 | 22篇 |
2020年 | 44篇 |
2019年 | 57篇 |
2018年 | 81篇 |
2017年 | 61篇 |
2016年 | 72篇 |
2015年 | 46篇 |
2014年 | 60篇 |
2013年 | 285篇 |
2012年 | 100篇 |
2011年 | 105篇 |
2010年 | 73篇 |
2009年 | 49篇 |
2008年 | 122篇 |
2007年 | 114篇 |
2006年 | 95篇 |
2005年 | 72篇 |
2004年 | 68篇 |
2003年 | 72篇 |
2002年 | 64篇 |
2001年 | 64篇 |
2000年 | 58篇 |
1999年 | 53篇 |
1998年 | 35篇 |
1997年 | 22篇 |
1996年 | 33篇 |
1995年 | 32篇 |
1994年 | 21篇 |
1993年 | 21篇 |
1992年 | 37篇 |
1991年 | 24篇 |
1990年 | 24篇 |
1989年 | 22篇 |
1988年 | 27篇 |
1987年 | 29篇 |
1986年 | 27篇 |
1985年 | 29篇 |
1984年 | 24篇 |
1983年 | 19篇 |
1982年 | 23篇 |
1981年 | 21篇 |
1980年 | 20篇 |
1979年 | 18篇 |
1978年 | 30篇 |
1977年 | 25篇 |
1976年 | 19篇 |
1975年 | 24篇 |
1974年 | 18篇 |
1968年 | 23篇 |
排序方式: 共有2638条查询结果,搜索用时 31 毫秒
971.
Jennifer B. Unger Michele D. Kipke Thomas R. Simon Susanne B. Montgomery Christine J. Johnson 《American journal of community psychology》1997,25(3):371-394
Although understanding of the subsistence patterns, service utilization, and HIV-risk behaviors of homeless youths and young adults is increasing, relatively little is known about the epidemiology of mental health problems in this group or the relationships between mental health problems and substance use. This study measured symptoms of depression, low self-esteem, ADHD, suicidality, self-injurious behavior (SIB), and drug and alcohol use disorder in a sample of homeless youth and young adults living in Hollywood, CA. Results indicated extremely high prevalences of mental health problems, as compared with corresponding rates of mental health problems found among housed youths in previous studies. Prevalence of mental health problems differed by age and ethnicity. African Americans were at lower risk of suicidal thoughts and SIB than were those of other ethnicities. Older respondents and females were at increased risk of depressive symptoms, and younger respondents were at increased risk of SIB. Previous history of sexual abuse and/or assault was associated with increased risk of suicidality and SIB. Risk factors for drug abuse disorder included ethnicity other than African American, homelessness for 1 year or more, suicidality, SIB, depressive symptoms, and low self-esteem. Risk factors for alcohol abuse disorder included male gender, white ethnicity, homelessness for 1 year or more, suicidality, and SIB. Extremely high rates of mental health problems and substance abuse disorders in this sample suggest the need for street-based and nontraditional mental health services targeted toward these youths and young adults. 相似文献
972.
The relation between body weight and responding established with unsignaled delayed reinforcement was investigated. In three experiments, naive rats were deprived to either 70%, 80%, or 90% of ad libitum weight and were then exposed to tandem variable-interval 15-s differential-reinforcement-of-other-behavior 30-s schedules. The tandem schedule defined a resetting unsignaled delay-of-reinforcement procedure. In the first experiment, speed of magazine training, acquisition of lever pressing, and final rate of lever pressing were related to body weight. In the next experiment, lever pressing was established and maintained in rats that were magazine trained at 70% of ad libitum weight but that were then exposed to the delay procedure at 90% of ad libitum weight. Responding did not change consistently either across or within subjects in subsequent conditions in which body weight was manipulated. In the final experiment, lever pressing was established and maintained with delayed reinforcement in the absence of magazine training for each of 2 rats at 70% and for 1 of 2 rats at 90% of ad libitum weight. The results further illuminate the conditions under which responding can be established in the absence of training and when such responses are reinforced only following an unsignaled delay period. 相似文献
973.
Williams B 《Journal of the experimental analysis of behavior》1997,67(2):255-258
974.
Williams B 《Journal of the experimental analysis of behavior》1997,68(1):133-141
The phenomenon of contrast has been studied from two quite separate perspectives, one derived from the classic studies of incentive contrast such as Crespi (1942) and the other from the study of behavioral contrast within behavior analysis. This book reviews both of these types of contrast effects and finds both differences and similarities between them. Still at issue is the validity of the interpretation of contrast that assumes that the value of some target level of reward is modified in inverse relation to the level of reward from other sources in the same context. This concept works well for the classic studies of incentive contrast, but is challenged by the emerging importance of anticipatory contrast and the finding in both of the separate research traditions that anticipatory contrast is inversely related to other measures of reinforcement value. 相似文献
975.
Basilia Softas-Nall Tracy D. Baldo Scott C. Williams 《Journal of multicultural counseling and development》1997,25(4):234-243
This study investigated the perceptions of counselors-in-training of Black, Hispanic, and White male and female adolescents in a teen pregnancy situation. Findings and implications for counselor training are discussed. 相似文献
976.
Warren J. Carlson William B. Williams Howard Davol 《Journal of abnormal child psychology》1984,12(2):245-260
Both normal and antisocial children were extensively observed in their natural home environments. A factor analysis of the baseline data was conducted that differed from the typical factor study in two respects. Equal numbers of deviant and nondeviant behaviors were included in the analysis, and the unit of analysis was the rate-per-minute occurrence of actual child behavior. The factor structure was interpretable, and scaling of the dimensions-I, Verbal Emotionality, II, Physical Dependency, HI, Social Involvement, IV, Hostile: Controlling, and V, Hostile: Impulsive-separated groups of normal, socially aggressive, hyperactive-aggressive, and stealing children. Reported differences between aggressive and stealing children on rates of total aversive behavior were found to be due to differences in the verbal behaviors loading on the first factor.The data reported in this paper were collected with support from a grant from the National Institute of Mental Health, Section on Crime and Delinquency, Grant No. MH 15985 to Oregon Social Learning Center. The authors wish to thank Gerald R. Patterson for granting access to the data files and for very patient continuing support and advice. 相似文献
977.
Jung's theory of psychological types provided the conceptual framework for a study of personality characteristics implicated in marital relationships. Partners in 20 couples completed the Myers-Briggs Type Indicator and a series of open-ended questions describing their marital relationships. As predicted, (a) type similarity was more characteristic than type dissimilarity, particularly on sensation-intuition and thinking-feeling preferences, (b) sensation-intuition preferences were reflected in perceptions of qualities valued in self and spouse, (c) thinking-feeling preferences were significantly related to reported satisfaction in marriage, and (d) intuitives were more open to changes in the relationship than were sensing types. Marital problems were highly diverse, and were not related in any clear way to type patterns in individuals or dyads. 相似文献
978.
B A Williams 《Journal of the experimental analysis of behavior》1984,42(3):469-483
Interest in operant research on stimulus control has declined at the same time that much interest has burgeoned in nonoperant areas. Several examples of this shift toward traditional learning theory are considered, all of which have sponsored theoretical approaches that attempt to characterize the underlying associative units. These theoretical approaches are defended on the grounds that they have generated a deeper understanding of a variety of often puzzling phenomena. My projection is that future research will be determined even more strongly by theories about the structure of associations. Particular issues for which such discussion will have major impact include (1) whether conditional stimulus control is qualitatively different than simpler forms of stimulus control, (2) whether stimulus control is organized hierarchically, and (3) the origin of categories of stimulus equivalence. 相似文献
979.
The study examined timing control in clumsy children and employed the Wing-Kristofferson (1973) model of repetitive movements in an attempt to identify the locus of timing control difficulties in clumsy children. Two groups of children classified as normal and clumsy (ages 6-7 and 9-10) performed tapping and perception of duration and loudness tasks. Results indicated that clumsy children were significantly more variable than normal children in maintaining a set rate of tapping and in accurately judging time intervals. Evidence indicated that the source of timing control problems in clumsy children may be in a central timekeeping mechanism, possibly the cerebellum. 相似文献
980.
Interest in the association between personality characteristics and physical health has been renewed in recent years. Theory and research in this area has also been complicated by conceptual and methodological limitations. The present article briefly reviews this literature and discusses the advantages and limitations of the five-factor model of personality as an integrating framework for studies of personality and health. The model has already been fruitfully applied in several contexts, and more possibilities exist. Although it has some potential limitations, the application of the five-factor model--as well as other aspects of current personality theory and research--is likely to facilitate progress in the study of how personality influences health. 相似文献