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151.
We examined links among three dimensions of youth involvement (intensity, duration, and engagement) in Boy Scouts of America (BSA), an international out‐of‐school time (OST) youth development program designed to promote moral and performance character in boys. Using data from 737 youth and their parents who participated in one of 40 BSA program sites (commonly referred to as “packs”), we first considered how individual‐ and pack‐level measures of program involvement were differentially linked with character development. Next, we examined whether pack‐level involvement characteristics moderate individual‐level involvement characteristics, hypothesizing that highly involved packs would serve to further enhance the positive effects of high levels of individual involvement. Results indicated engagement was the strongest, most frequent predictor of increases in both moral and performance character. Although there were no direct effects of pack‐level intensity, duration, or engagement, the effects of individual‐level engagement were moderated by pack‐level engagement, suggesting that the largest increases in moral and performance character occurred among highly engaged youth who were enrolled in highly engaged packs. These results highlight the need to examine multiple dimensions of OST program involvement simultaneously, and suggest that strengthening youth engagement in programming may provide a means for enhancing the positive effects of high‐quality youth programming.  相似文献   
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153.
The authors describe and use four methods for detecting Differential Item Functioning in polytomous items: Mantel, Generalized Mantel-Haenszel (GMH), Ordinal Logistic Regression (RLO), and Discriminant Logistic Regression (RLD). For each procedure, the theoretical model and the measure of effect size are described. The data from the "Reading Comprehension Test" from the PISA2000 evaluation program were analyzed using a cross-validation design. Two booklets were independently evaluated in the American and Spanish samples. Adopting as decision rule the significance of the statistical test and the measurement of the effect size, agreement among the evaluated procedures was total for two of the analyzed items.  相似文献   
154.
Establishing behavioral consistency in serial homicide offending behavior is essential when linking homicides together and to a common offender. An examination of 35 serial homicide behaviors utilized by 90 offenders in 450 serial homicide cases was carried out to identify whether these offenders consistently performed the same behaviors across their series of homicides and whether it is more effective to examine individual behaviors or groupings of behaviors in order to identify behavioral consistency. This study provides the first empirically based evidence testing the use of using single behaviors as linking factors in linking homicide cases in a series, and shows that this method has inherent difficulties in accomplishing this, thus providing the first wave of empirical testing that questions current theories in the literature on serial homicide, which has suggested that signatures or specific key behaviors are important in understanding the consistency in an offender's behavior across the crimes. Recommendations for future studies on linking using signatures are suggested, including a more in-depth qualitative empirical evaluation of individual series.  相似文献   
155.
Although there is evidence that estradiol has effects in women and in animal models to reduce anxiety and depressive behavior and enhance performance in some cognitive tasks, this is not seen among all individuals. Given the interaction between estradiol and hypothalamic-pituitary-adrenal function, we hypothesized that an individual's prior exposure to stress may mitigate some of the subsequent effects of estradiol. To address this, rats were exposed to gestational stress, or not, to determine if stress exposure during development alters behavioral responses to estradiol in adulthood. If estradiol's effects on anxiety and cognitive behavior are modulated by prior stress experience, then gestationally-stressed rats administered estradiol should have decreased anti-anxiety (open field, elevated plus maze) behavior and cognitive performance in the inhibitory avoidance task. Offspring of dams that were exposed to restraint stress daily on gestational days 14-20, or no such manipulation, were used as adults either intact in behavioral estrus (high estradiol) or diestrus (low estradiol), or ovariectomized (OVX) with empty or estradiol-containing silastic implants. Rats were used for blood collection to determine plasma corticosterone and estradiol concentrations, or were used for behavioral testing. Compared with rats in diestrus or OVX and vehicle-replaced, rats in behavioral estrus and OVX rats with estradiol implants had higher estradiol concentrations, entered more central squares in an open field, spent more time on the open arms of the plus maze, and had a longer latency to crossover to the dark, shock-associated side of the inhibitory avoidance chamber. Gestational stress increased plasma corticosterone but not estradiol levels, decreased plus maze open arm time in cycling rats, and decreased inhibitory avoidance performance. Thus, estradiol and gestational stress can have opposite effects on anxiety and inhibitory avoidance performance.  相似文献   
156.
The authors tested the role of dispositions and self-regulatory mechanisms in the relation between social exclusion and self-defeating behavior. The authors manipulated the perception of social exclusion by giving participants feedback about the likelihood of their ending up alone. The authors randomly assigned participants to the following experimental conditions that varied by type of feedback: (a) social inclusion (n = 31), (b) social exclusion (n = 32), and (c) control (n = 30). Before receiving the feedback, each participant completed a questionnaire about his or her personality. Both before and after receiving the feedback, each participant also completed a questionnaire about self-regulatory variables. Participants then performed a task concerning a type of self-defeating behavior: misguided persistence. Results suggest that to avoid problems of adaptation, it is wise for psychologists to promote social self-efficacy, incremental implicit theories of ability, and positive emotion in groups threatened with social exclusion.  相似文献   
157.
Steroid modulation of cognitive function has focused on estrogen (E(2)), but progestins naturally co-vary with E(2) and may also influence cognitive performance. Spatial performance in the object placement task over endogenous hormonal states in which E(2) and progestins vary, and when E(2) and/or progestins were administered, was examined. Experiment 1: Rats in proestrus or estrus had significantly better performance in the object placement task than did diestrus rats. Experiment 2: Rats in the third trimester, post-partum, or lactation exhibited significantly better performance in the object placement task than did rats in the first trimester. Experiment 3: Ovariectomized (ovx) rats administered 17beta-estradiol (0.9 mg/kg), subcutaneously (sc), progesterone (P; 4 mg/kg, sc), or E(2) and P, immediately after training in the object placement task, performed significantly better when tested 4h later, than did control rats administered vehicle (sesame oil 0.2 cc). Experiment 4: ovx rats administered E(2) or P with a 1.5h delay after training in the object placement task, did not perform differently than vehicle-administered controls. Experiment 5: ovx rats administered post-training E(2), which has a high affinity for both E(2) receptor (ER)alpha and beta isoforms, or propyl pyrazole triol (PPT; 0.9 mg/kg, sc), which is more selective for ERalpha than ERbeta, had significantly better performance in the object placement task than did rats administered vehicle or diarylpropionitrile (DPN; 0.9 mg/kg, sc), an ERbeta selective ligand. Experiment 6: ovx rats administered P, or its metabolite, 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP; 4 mg/kg, sc), immediately post-training performed significantly better in the object placement task than did vehicle control rats. Thus, performance in the object placement task is better when E(2) and/or P are naturally elevated or when E(2), the ERalpha selective ER modulator PPT, P, or its metabolite, 3alpha,5alpha-THP, are administered post-training.  相似文献   
158.
A prenatal intervention designed to prevent the onset of major depressive episodes (MDEs) during pregnancy and postpartum was pilot tested at a public sector women’s clinic. The Mamás y Bebés/Mothers and Babies Course is an intervention developed in Spanish and English that uses a cognitive-behavioral mood management framework, and incorporates social learning concepts, attachment theory, and socio-cultural issues. The four goals of this project were to develop the intervention, assess its acceptability, test the feasibility of conducting a randomized trial with public sector patients, and obtain estimates of its effect size. Forty-one pregnant women at high risk for developing MDEs were randomized to the Mothers and Babies Course (n = 21) or a comparison condition (n = 20). Assessments occurred during pregnancy and at 1, 3, 6, and 12 months postpartum. Differences in terms of depression symptom levels or incidence of MDEs between the two groups did not reach statistical significance in this pilot trial. However, the MDE incidence rates of 14% for the intervention condition versus 25% for the comparison condition represent a small effect size (h = 0.28) that will be further examined in a larger scale study. The intervention was well received by the participants and implementation of a randomized trial appeared quite feasible as indicated by our follow-up rate of 91% at 12 months. Implications for the continuing development of preventive interventions for perinatal depression are discussed.  相似文献   
159.
160.
The social dominance behavior of dyads of unacquainted, same-sex 31/2 year-olds was observed in a familiar laboratory playroom under two conditions: A free play situation and a situation where candy was introduced. In each of the two conditions, a principal components analysis was used to explore two issues: the usefulness of the multivariate approach in devising a definition of dominance, and the cross-situational stability of the construct. In the free play session, the first principal component that emerged was consistent with a theoretical definition of dominance. This picture was disrupted by the introduction of candy in the second condition. However, a high correlation was found between the dominance hierarchies established in each situation. It was concluded that the multivariate analysis is a useful method for the study of dominance. The generalizability of social dominance across settings was discussed as a possible explanation for the high cross-situational stability.  相似文献   
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