全文获取类型
收费全文 | 546篇 |
免费 | 62篇 |
国内免费 | 27篇 |
出版年
2023年 | 16篇 |
2022年 | 12篇 |
2021年 | 18篇 |
2020年 | 27篇 |
2019年 | 33篇 |
2018年 | 27篇 |
2017年 | 50篇 |
2016年 | 33篇 |
2015年 | 19篇 |
2014年 | 26篇 |
2013年 | 103篇 |
2012年 | 13篇 |
2011年 | 16篇 |
2010年 | 12篇 |
2009年 | 23篇 |
2008年 | 21篇 |
2007年 | 21篇 |
2006年 | 22篇 |
2005年 | 11篇 |
2004年 | 15篇 |
2003年 | 12篇 |
2002年 | 9篇 |
2001年 | 6篇 |
2000年 | 11篇 |
1999年 | 10篇 |
1998年 | 6篇 |
1997年 | 6篇 |
1996年 | 7篇 |
1995年 | 11篇 |
1994年 | 9篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
排序方式: 共有635条查询结果,搜索用时 15 毫秒
521.
522.
Differentiability of Kruskal's stress at a local minimum 总被引:1,自引:0,他引:1
Jan De Leeuw 《Psychometrika》1984,49(1):111-113
It is shown that Kruskal's multidimensional scaling loss function is differentiable at a local minimum. Or, to put it differently, that in multidimensional scaling solutions using Kruskal's stress distinct points cannot coincide. 相似文献
523.
Silvia R. Kopf Mariano M. Boccia Carlos M. Baratti 《Neurobiology of learning and memory》1998,70(3):305-313
Male Swiss mice were tested 24 h after training in a one-trial step-through inhibitory avoidance task. Low subeffective doses of
-(+)-glucose (10 mg/kg, ip), but not its stereoisomer
-(−)-glucose (30 mg/kg, ip), administered immediately after training, and AF-DX 116 (0.3 mg/kg, ip), a presynaptic muscarinic receptor antagonist, given 10 min after training, interact to improve retention. Insulin (8 IU/kg, ip) impaired retention when injected immediately after training, and the effects were reversed, in a dose-related manner, by AF-DX 116 (0.3, 1.0, or 3.0 mg/kg, ip) administered 10 min following insulin. Since AF-DX 116 possibly blocks autoreceptors mediating the inhibition of acetylcholine release from cholinergic nerve terminals, the present data support the view that changes in the central nervous system glucose availability, subsequent to modification of circulating glucose levels, influence the activity of central cholinergic mechanisms involved in memory storage of an inhibitory avoidance response in mice. 相似文献
524.
A Bayesian approach to nonlinear latent variable models using the Gibbs sampler and the metropolis-hastings algorithm 总被引:1,自引:0,他引:1
Nonlinear latent variable models are specified that include quadratic forms and interactions of latent regressor variables as special cases. To estimate the parameters, the models are put in a Bayesian framework with conjugate priors for the parameters. The posterior distributions of the parameters and the latent variables are estimated using Markov chain Monte Carlo methods such as the Gibbs sampler and the Metropolis-Hastings algorithm. The proposed estimation methods are illustrated by two simulation studies and by the estimation of a non-linear model for the dependence of performance on task complexity and goal specificity using empirical data. 相似文献
525.
Yuchung J. Wang 《Psychometrika》1997,62(2):267-284
Ak-dimensional multivariate normal distribution is made discrete by partitioning thek-dimensional Euclidean space with rectangular grids. The collection of probability integrals over the partitioned cubes is ak-dimensional contingency table with ordered categories. It is shown that loglinear model with main effects plus two-way interactions provides an accurate approximation for thek-dimensional table. The complete multivariate normal integral table is computed via the iterative proportional fitting algorithm from bivariate normal integral tables. This approach imposes no restriction on the correlation matrix. Comparisons with other numerical integration algorithms are reported. The approximation suggests association models for discretized multivariate normal distributions and contingency tables with ordered categories.The contingency-table approach occurred to me while I was collaborating with Paul Holland of the Educational Testing Service in 1985 on bivariate dependence functions. Holland maintains a belief that the continuous can learn from the discrete. This work is a reassertion of his claim.This research was sponsored by the National Science Council, Republic of China. 相似文献
526.
Food delivery as a conditional stimulus: Feature-learning and memory in pigeons 总被引:1,自引:1,他引:0
下载免费PDF全文
![点击此处可从《Journal of the experimental analysis of behavior》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Three experiments investigated the learning and memory of discriminations based on presence versus absence of a pre-trial food delivery. In Experiment 1 half the illuminations of a response key were followed by food regardless of the subject's behavior. In one group an extra food delivery preceded only reinforced trials (feature-positive condition), whereas in a second group it preceded only nonreinforced trials (feature-negative condition). Key pecks and approaches revealed more rapid and superior discrimination learning in the first group. Experiment 2 replicated the results of Experiment 1 but yielded no evidence that greater “unexpectedness” of pretrial food conditions facilitates discriminative performance. In Experiment 3, individual pigeons trained on a conditional discrimination exhibited a within-subject feature-positive superiority. Delay between pretrial and trial stimuli interacted with feature-positive versus feature-negative training in both the between-group (Experiment 2) and within-subject (Experiment 3) procedures: performance was decremented at both short and long delays in the feature-positive condition but was decremented only at longer delays in the feature-negative condition. The feature-positive superiority obtained here is incompatible with explanations based on either the general concept of “perceptual organization” or on the conditional nature of feature-negative discriminations. 相似文献
527.
We present a new model of remembering in the context of conditional discrimination. For procedures such as delayed matching to sample, the effect of the sample stimuli at the time of remembering is represented by a pair of Thurstonian (normal) distributions of effective stimulus values. The critical assumption of the model is that, based on prior experience, each effective stimulus value is associated with a ratio of reinforcers obtained for previous correct choices of the comparison stimuli. That ratio determines the choice that is made on the basis of the matching law. The standard deviations of the distributions are assumed to increase with increasing retention-interval duration, and the distance between their means is assumed to be a function of other factors that influence overall difficulty of the discrimination. It is a behavioral model in that choice is determined by its reinforcement history. The model predicts that the biasing effects of the reinforcer differential increase with decreasing discriminability and with increasing retention-interval duration. Data from several conditions using a delayed matching-to-sample procedure with pigeons support the predictions. 相似文献
528.
Huynh Huynh 《Psychometrika》1994,59(1):77-79
By use of an inequality of Marcus and Lopes for elementary symmetric functions, a new proof is presented for the following result by Ghurye and Wallace: Given that the independent random variablesX
j
are Bernoulli with success probabilityp
j
() strictly between 0 and 1 and nondecreasing in, the sum X
j
has monotone likelihood ratio. 相似文献
529.
Judith L. Navratil B.A. Stephanie M. Green M.S. Rolf Loeber Ph.D. Benjamin B. Lahey Ph.D. 《Journal of child and family studies》1994,3(1):89-106
A number of techniques are described to prevent attrition of four different categories of subjects in a longitudinal study of deviant behavior.Difficult to schedule subjects required persistence, empathy and flexibility to ensure their continued participation.Reluctant subjects were persuaded to participate by taking special care to build rapport with that family.Subjects who initially refused were turned around by assuming that a subject's refusal one year was circumstantial, and approaching that subject the following year with personalized correspondence that emphasized the importance of their contribution to the research. Persistence was an important factor in successfully locating and recruitingtransient subjects. 相似文献
530.
Performances on ratio and interval schedules of reinforcement: Data and theory 总被引:7,自引:7,他引:0
下载免费PDF全文
![点击此处可从《Journal of the experimental analysis of behavior》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Baum WM 《Journal of the experimental analysis of behavior》1993,59(2):245-264
Two differences between ratio and interval performance are well known: (a) Higher rates occur on ratio schedules, and (b) ratio schedules are unable to maintain responding at low rates of reinforcement (ratio “strain”). A third phenomenon, a downturn in response rate at the highest rates of reinforcement, is well documented for ratio schedules and is predicted for interval schedules. Pigeons were exposed to multiple variable-ratio variable-interval schedules in which the intervals generated in the variable-ratio component were programmed in the variable-interval component, thereby “yoking” or approximately matching reinforcement in the two components. The full range of ratio performances was studied, from strained to continuous reinforcement. In addition to the expected phenomena, a new phenomenon was observed: an upturn in variable-interval response rate in the midrange of rates of reinforcement that brought response rates on the two schedules to equality before the downturn at the highest rates of reinforcement. When the average response rate was corrected by eliminating pausing after reinforcement, the downturn in response rate vanished, leaving a strictly monotonic performance curve. This apparent functional independence of the postreinforcement pause and the qualitative shift in response implied by the upturn in variable-interval response rate suggest that theoretical accounts will require thinking of behavior as partitioned among at least three categories, and probably four: postreinforcement activity, other unprogrammed activity, ratio-typical operant behavior, and interval-typical operant behavior. 相似文献