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   30494篇
  免费   465篇
  国内免费   5篇
  30964篇
  2021年   88篇
  2020年   149篇
  2019年   206篇
  2018年   3715篇
  2017年   3025篇
  2016年   2473篇
  2015年   381篇
  2014年   309篇
  2013年   1048篇
  2012年   931篇
  2011年   2796篇
  2010年   2757篇
  2009年   1699篇
  2008年   2008篇
  2007年   2478篇
  2006年   301篇
  2005年   437篇
  2004年   389篇
  2003年   322篇
  2002年   289篇
  2001年   328篇
  2000年   327篇
  1999年   235篇
  1998年   117篇
  1997年   99篇
  1996年   99篇
  1993年   87篇
  1992年   162篇
  1991年   163篇
  1990年   159篇
  1989年   140篇
  1988年   125篇
  1987年   131篇
  1986年   144篇
  1985年   146篇
  1984年   132篇
  1983年   104篇
  1982年   91篇
  1981年   89篇
  1979年   147篇
  1976年   90篇
  1975年   110篇
  1974年   135篇
  1973年   118篇
  1972年   104篇
  1971年   100篇
  1970年   112篇
  1969年   106篇
  1968年   108篇
  1967年   129篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
221.
In a randomized clinical trial, multisystemic family preservation was shown to significantly reduce rates of criminal activity and incarceration in a sample of 84 serious juvenile offenders and their multi-need families. In the current study, archival records were searched for re-arrest an average of 2.4 years post-referral. Survival analysis showed that youths who received multisystemic family preservation were less likely to be re-arrested than were youths who had received usual services. Such results represent the first controlled demonstration that family preservation, when delivered via a clearly specified treatment model, has lasting effects with serious juvenile offenders. Implications for family preservation and juvenile justice research are discussed.  相似文献   
222.
Previous studies of infants’ ability to integrate and to utilize relative motion as information for form in the absence of structural cues have primarily involved motions that are uniform in rate, direction, and path within the form to be constructed. In the present study, we examined infants’ ability to integrate relative motion information from motions that are nonuniform along these dimensions, and from this integrative process to construct a coherently rotating two-dimensional form. Infants’ ability to integrate nonuniform motion was measured with regard to their ability to discriminate the rotating form from a noncoherent control display containing the same absolute motions. The results showed that discrimination of the coherent and incoherent displays was not demonstrated until 7 months of age. Two additional experiments were conducted to rule out the possibility that this discrimination was based on the detection of local regions of coherence, rather than the perception of the global rotating form. In both experiments, the results did not support discrimination based exclusively on local cues alone. From the combined results of all three experiments, we conclude that infants demonstrate the capacity to integrate the information contained within nonuniform trajectories into a coherent structure by 7 months of age.  相似文献   
223.
The concept of systemic quantization of behavior was used to study the interaction between dominant motivation and reinforcement on brain neurons. Feeding and escape were used as experimental models. Results showed that feeding and escape motivations are based on the mechanisms of ascending activating influences of lateral or ventromedial hypothalamic centers, respectively, on cortical neurons. Feeding and escape motivations evoked by electrical stimulation of hypothalamus, or the ones occurring naturally, modify the responses of single neurons of sensorimotor and insular cortex to sensory stimuli, to microiontophoretic application of neurotransmitters and neuropeptides, and especially to reinforcement. Dominant motivations are reflected in the burst-like activity and in a specific pattern of interpulse intervals of single units in various brain structures. Reinforcement transforms this activity into a regular pattern and also changes the neuronal responses of hypothalamic feeding and escape centers, to electrical stimulation and to microiontophoretic application of oligopeptides. Specific patterns of the unit responses to conditioned stimuli in the course of consecutive reinforcement was determined. After several instances of reinforcement, especially after repetitive reinforcement, the brain neurons influenced by the dominant motivation begin to produce specific protein molecules that are important for organization of an appropriate type of behavior. This process can be blocked by protein synthesis inhibitors.  相似文献   
224.
225.
A proximal-distal theoretical framework was developed to examine the multivariate roots of homophobia. Using data from a sample of 288 undergraduates who had participated in a computer-assisted panel study over a three-year period, the effects on homophobia of distal and proximal family factors (e. g., parental education and family environment), distal and proximal individual factors (e. g., personality constructs and current beliefs), and proximal individual-situational factors (e. g., acquaintance with homosexuals) were tested in regression analyses. Both analyses employing sets of variables varying in proximity to the homophobic attitude and hierarchical regression employing variables contributing significantly in each set supported the proposed framework. All sets predicted significantly when regressed separately on homophobia; the sets containing the distal factors contributed most weakly, and the sets containing the proximal factors contributed most strongly. In hierarchical regression analysis, this pattern maintained such that the incremental increase in r2 decreased with the addition of each more distal set, with the most distal factors failing to contribute significantly to the prediction. The importance of study findings for attitude change efforts is discussed.  相似文献   
226.
A functional analysis of the self-injurious behavior (SIB) of 3 adults with profound developmental disabilities showed that each engaged in SIB in more than one assessment condition. Such outcomes may result from a failure to isolate the variable maintaining SIB, or they may reflect multiple sources of control over SIB. In order to identify more clearly the determinants of SIB, each subject was exposed to a series of treatments appropriate to one or both of the apparent functions of SIB. These treatments, applied sequentially on baselines appropriate to each behavioral function, identified the maintaining variables for SIB through differential outcomes across baselines. Results indicated that the SIB of 2 subjects was multiply controlled, confirming the outcomes of the functional analysis. However, the SIB of the 3rd subject was eliminated using a treatment designed for a single function, suggesting spurious results of the original assessment. Alternative interpretations of undifferentiated assessment data are discussed, as are analysis and treatment issues related to multiply determined behavior disorders.  相似文献   
227.
Twenty-six infants, 3 to 23 months old, were trained on fixed-interval schedules ranging from 10 s to 80 s. The operant response was touching an illuminated location on a touch-sensitive screen, and 20 s of cartoon presentation was the reinforcer. The subjects were also trained in a six-phase self-control procedure in which the critical phases involved choice between 20 s of cartoon available after a 0.5-s delay (impulsive choice) and 40 s of cartoon delayed for 40 s (self-controlled choice). All the youngest children (3 to 5 months) showed long postreinforcement pauses on the fixed-interval schedule, with most intervals involving the emission of a single, reinforced, response, and all made self-controlled choices. Older subjects (9 to 23 months) either produced the same pattern as the younger ones on the fixed-interval schedule (classified as pause-sensitive subjects) or produced short pauses and higher steady response rates (classified as pause-insensitive subjects). All pause-sensitive subjects made self-controlled choices in the self-control condition, and all pause-insensitive subjects made impulsive ones.  相似文献   
228.
The Gender Role Journey concept was developed to help women and men explore their gender role changes and transitions. A 34-item Gender Role Journey Measure (GRJM) was conceptualized and developed through empirical methods. The construct validity of the five phases of the gender role journey is assessed. The GRJM and the Personal Attributes Questionnaire (PAQ) were given to a sample of women and men (N=878). The sample was predominantly Caucasian from a mixed ethnic background. Principle factor analysis indicated three meaningful factors: Acceptance of Traditional Gender Roles; Gender Role Ambivalence, Confusion, Anger, and Fear; and Personal-Professional Activism. Moderately high test-retest and internal consistency reliabilities were found for each of the factors. Gender differences and gender by PAQ interactions were found for all three of the factors of the GRJM. Implications for future research, teaching, and workshops are suggested.This article was presented at the 99th convention of the American Psychological Association, San Francisco, California, August 1991. It was supported by a grant from the Research Foundation of the University of Connecticut, Storrs, Connecticut.  相似文献   
229.
V D Gifford  M M Dean 《Adolescence》1990,25(100):799-802
The purpose of this study was to determine the type of school organization that most benefited ninth-grade students. Results indicated that ninth graders in the junior high school setting participated significantly more in extracurricular activities and achieved significantly higher academically than did ninth graders in the senior high school setting.  相似文献   
230.
D B Stein  E D Smith 《Adolescence》1990,25(100):891-904
This study compared the REST (Real Economy System for Teens) program with traditional talk therapy in the treatment of oppositional defiant adolescents. The REST program uses rules for five target behaviors: room care, personal hygiene, completion of chores, abusiveness, and safety violations. Objective measures and subjective parental ratings were taken. Twenty-five adolescents were assigned to each therapy group. In the REST program the adolescent was provided with only food and shelter. The adolescent had to earn money through the REST allowance program to pay for everything else. Earning the allowance was made contingent upon compliance with all rules for the five target behaviors. The results showed significantly greater improvement on all target behaviors for the REST program than for traditional therapy. In addition, parents of adolescents in the REST group reported that their adolescents seemed happier, more relaxed, and closer to them.  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