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31.
Human Signal-detection Performance: Effects Of Signal Presentation Probabilities And Reinforcer Distributions
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University students participated in one of four standard two-choice signal-detection experiments in which signal presentation probability was varied and the reinforcement distribution was held constant and equal. In Experiments 1, 3 and 4, subjects' performance showed a systematic response bias for reporting the stimulus presented least often. Experiments 1 and 4 showed that this effect was reliable with extended training and monetary, rather than point, reinforcement. In Experiment 2, all correct responses were signaled in some way, and this produced the opposite relationship between signal presentation probability and response bias. Experiments 1 and 3 found that explicitly deducting money (intended as punishment) for equal numbers of incorrect responses on each alternative, or varying the obtained overall rate of reinforcement, produced no clear change in response bias. The bias, shown by humans, for reporting the stimulus presented least often remains a challenge for theories of stimulus detection. 相似文献
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Eight pigeons were trained on a delayed presence-versus-absence discrimination paradigm in which a sample stimulus was presented on some trials but not on others. If a sample was presented, then a response to one choice key produced food. If no sample was presented, a response to the other choice key produced food. The basic finding was that performance remained constant and well above 50% correct on no-sample trials as the retention interval increased, whereas performance dropped precipitously (to below 50% correct) on sample trials. In the second phase of the experiment, all of the trials were no-sample trials, and reinforcers were delivered probabilistically for one group of pigeons and according to time-based schedules for the other group. The exact reinforcement probabilities used in Phase 2 were those calculated to be in effect on no-sample trials in Phase 1 (according to a discrete-state model of performance). Subjects did not show exclusive preference for the richer alternative on no-sample trials in the first phase, but those in the probabilistic group developed near-exclusive preference for the richer alternative during the second phase. These data are inconsistent with the predictions of the discrete-state model, but are easily accommodated by an account based on signal detection theory, which also can be applied effectively to discrimination of event duration and the “subjective shortening” effect. 相似文献
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肝癌的手术治疗中肝切除和肝移植在适应证的选择、手术方式、围手术期的管理上有很大的不同,但在治疗目的、手术和解剖技术上又有共同之处。这种对立统一的关系对指导临床工作有重要意义。结合我国实际,用辩证的方法和发展的观点选择恰当的方法是手术治疗肝癌的关键。 相似文献
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通过研究颈椎后纵韧带骨化患者的不同手术方式对术后效果的影响,回顾性对分别行前路、后路手术治疗的颈椎后纵韧带骨化患者127例进行5年~10年的随访并依据手术前后不同时期的影像学结果及神经功能改善情况进行分析,探讨椎管狭窄率和颈椎序列变化等因素对手术方式的选择及术后疗效的影响。结果显示,前路手术组术后能够维持并改善颈椎前凸... 相似文献
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通过口腔疣状癌特殊类型发现与分型标准建立的探讨,阐明了口腔疣状癌分型的重要性以及对治疗的重要指导意义。并通过总结说明,任何一门学科的发展既依赖于科学技术的进步,也要求科学工作者有怀疑的精神,同时应具有一定的哲学思想,将哲学思想的各种理论贯穿研究其中。 相似文献
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There is increasing focus on the neurophysiological underpinnings of brain activations, giving birth to an emerging branch of neuroscience – neuroenergetics. However, no common definition of “brain activation” exists thus far. In this article, we define brain activation as the information-driven reorganization of energy flows in a population of neuroglial units that leads to an overall increase in energy utilization in this population. On the basis of this definition, the key aspects of modern biochemical and biophysical approaches to neuroenergetics are considered from the perspective of the links between these approaches within the context of the free energy minimization principle and the neurophysiological conception of deviance detection. In this light, we consider brain basal activity as subserving internal representations of the environment (predictive coding), and brain activation as reflecting the level of deviance from predictive coding. 相似文献
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Alfredo Campos María Angeles González Angeles Amor 《The Journal of general psychology》2013,140(4):399-413
The effectiveness of the mnemonic-keyword method was investigated in 4 experiments in which participants were required to learn the lst-language (L1, Spanish) equivalents of a list of 30 2nd-language words (L2, Latin). Experiments 1 (adolescents) and 2 (adults) were designed to assess whether the keyword method was more effective than the rote method; the researcher supplied the keyword, and the participants were allowed to pace themselves through the list. Experiments 3 (adolescents) and 4 (adults) were similar to Experiments 1 and 2 except that the participants were also supplied with a drawing that illustrated the relationship between the keyword and the L1 target word. All the experiments were performed with groups of participants in their classrooms (i.e., not in a laboratory context). In all experiments, the rote method was significantly more effective than was the keyword method. 相似文献