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151.
Although use of the standardized mean difference in meta-analysis is appealing for several reasons, there are some drawbacks. In this article, we focus on the following problem: that a precision-weighted mean of the observed effect sizes results in a biased estimate of the mean standardized mean difference. This bias is due to the fact that the weight given to an observed effect size depends on this observed effect size. In order to eliminate the bias, Hedges and Olkin (1985) proposed using the mean effect size estimate to calculate the weights. In the article, we propose a third alternative for calculating the weights: using empirical Bayes estimates of the effect sizes. In a simulation study, these three approaches are compared. The mean squared error (MSE) is used as the criterion by which to evaluate the resulting estimates of the mean effect size. For a meta-analytic dataset with a small number of studies, theMSE is usually smallest when the ordinary procedure is used, whereas for a moderate or large number of studies, the procedures yielding the best results are the empirical Bayes procedure and the procedure of Hedges and Olkin, respectively. 相似文献
152.
In a study among 72 nurses, the affective consequences of social comparison were examined and related to neuroticism (N) and to social comparison orientation (SCO). Participants were confronted with a bogus interview with an upward versus a downward comparison target. Positive affect and identification were higher, and negative affect was lower, in the upward than in the downward comparison condition. Independent of their SCO, the higher individuals were in N, the less they identified with the upward comparison target, the more they identified with the downward comparison target, and the less positive affect they showed following confrontation with the upward comparison target. In contrast, independent of their level of N, the higher individuals were in SCO, the more negative affect they showed following confrontation with the downward comparison target. The effects on negative affect stayed the same when controlling for positive affect, and the effects on positive affect stayed the same when controlling for negative affect. These effects were also obtained when perceived direction was used as a predictor instead of the experimentally manipulated direction. It is concluded that, although N and SCO are correlated, these variables seem to have independent and distinct effects upon the responses to social comparison information. 相似文献
153.
According to the two-thirds power law the cube of the speed of a drawing movement is proportional to the radius of curvature of the trajectory, and the coefficient of proportionality has the meaning of mechanical power. We derive this empirical law from the variational principle known in physics as the principle of least action. It states that if a movement between two points of a given path obeys the two-thirds law, then the amount of work required to execute a trajectory in a fixed time is minimal. In this strict sense one may say that among infinitely many ways to execute a given path, the central nervous system chooses the most economical. We show that the kinematic equations for all drawing movements are solutions of a certain differential equation with a single (time-variable) coefficient. We consider several special cases of drawing movements corresponding to simplest forms of this coefficient. Copyright 2001 Academic Press. 相似文献
154.
Displays were presented consisting of a perspective projection of a regular square grid, made up of vertical and horizontal equally spaced white lines, that was slanted in depth. The surface was viewed monocularly, through a circular aperture. A range of slants was shown (0 degree, 10 degrees, 20 degrees, 30 degrees, 40 degrees, 50 degrees, or 60 degrees) and the observers' task was to match the slant by means of a mouse-driven probe. The viewing distance (50, 75, or 100 cm) as well as the focal distance (25, 50, 75, 100, or 125 cm) were varied. We expected the estimation error to be smallest when the viewing distance and the focal distance coincided. This was not the case. Instead, subjects seemed to use the perspective deformation of the texture elements in the stimulus display to make a slant estimation, regardless of the specific combination of viewing distance and focal distance. 相似文献
155.
Scahill L Lombroso PJ Mack G Van Wattum PJ Zhang H Vitale A Leckman JF 《Perceptual and motor skills》2001,92(2):419-432
The effects of heat on tic symptoms were studied in a sample of 78 adults with Tourette syndrome. 62 men and 16 women completed a survey concerning the type, onset, and course of their tics. 10 adult male subjects also participated in a thermal challenge during which ambient temperature was raised from 22 degrees C to 35 degrees C following a control period. Of the 78, 24% or 19 reported increased tics upon exposure to heat. Compared to the remaining 59 subjects, there were no differences in sex distribution, current age, or overall course of illness. In the thermal challenge, there was general increase in tics that was correlated with sweat rate (r = .55, p = .001). This effect was prominent in 5 of 10 subjects (rs = .29 to .63). There were no mean differences in current age, age of onset, or current severity of symptoms between the five subjects of each group. Tic symptoms in a subgroup of patients with Tourette syndrome may be sensitive to heat. Abnormal heat regulation is not a likely explanation for the observed increase in tics. The increase may be due to normal heat-loss mechanisms through dopaminergic pathways. 相似文献
156.
Andersen MB Van Raalte JL Brewer BW 《Professional psychology, research and practice》2001,32(1):12-18
Although the parent discipline of sport psychology is psychology, the delivery of sport psychology services has its main roots in physical education and sports science (motor learning and control, skill acquisition). Thus, sport psychologists may look more like coaches than they look like clinicians or counselors. In this article, the authors trace the evolution of sport psychology services and contrast the temporal, spatial, and delivery issues of applied sport psychology with more mainstream counseling and clinical psychology. The looser boundaries of sport psychologist practice have both benefits and dangers, and the authors offer some examples to professional psychologists who are thinking of expanding their delivery of service to athletes and coaches. 相似文献
157.
Jan A. Feij Mandy E.G. Van Der Velde Ruben Taris Toon W. Taris 《International Journal of Selection & Assessment》1999,7(1):12-25
This two-phase panel study examines the development of the congruence between vocational interests and perceived skill requirements. Participants were 492 Dutch men and women between 18 and 26 years old, with a paid job in both phases. Three hypotheses inspired by the theory of work adjustment (Dawis and Lofquist 1984) and congruence theory (Holland 1992) were tested, using a composite index of fit proposed by Cronbach and Gleser (1953). The first hypothesis proposing that participants experiencing incongruence between their vocational interests and their perceived skill requirements are dissatisfied with their job was supported. The hypothesis that incongruence has a positive relationship with job change and a negative relationship with tenure was not confirmed. The expectation that the congruence between vocational interests and perceived skill requirements increases over time was confirmed. Furthermore, exploring determinants of change in vocational interests and perceived skill requirements, it was found that change in these domains was predicted by different variables, educational level being the only common factor. It is concluded that this study supports the longitudinal propositions of prevailing work-related person-environment fit theories. 相似文献
158.
159.
This work evaluated the prospect that organizational accounts of the retention of list information by monkeys might be an
artifact of familiarity with conditional relationships. Seven sophisticated macaques were trained on four five-item lists.
Each acquisition selectively excluded one of the internal conditional pairs of the typical four-problem sequence (AB,BC,CD,DE)
that defines a five-item serially ordered list. Then, all possible novel pairings and the trained pairs appeared together
in a test. After this, the previously omitted pair was trained and animals were retested. On all tasks, initial tests revealed
little organization and much intersubject variability of characteristic choice strategies, but subsequent inclusion of all
four conditional pairs always yielded organized serial choice. On both the four-problem tests and in a later retention, errors
were directly related to interitem distance between the objects paired on test trials. These results helped to specify the
conditions required for demonstration of non-human primate analogs of transitivity, and showed that even sophisticated monkeys
organize information in retention only if they know all interitem relationships.
Received: 7 October 1998 / Accepted after revision: 10 October 1999 相似文献
160.