全文获取类型
收费全文 | 4208篇 |
免费 | 224篇 |
国内免费 | 2篇 |
出版年
2023年 | 52篇 |
2022年 | 84篇 |
2021年 | 108篇 |
2020年 | 146篇 |
2019年 | 149篇 |
2018年 | 218篇 |
2017年 | 233篇 |
2016年 | 180篇 |
2015年 | 122篇 |
2014年 | 133篇 |
2013年 | 549篇 |
2012年 | 307篇 |
2011年 | 309篇 |
2010年 | 193篇 |
2009年 | 113篇 |
2008年 | 263篇 |
2007年 | 204篇 |
2006年 | 184篇 |
2005年 | 119篇 |
2004年 | 97篇 |
2003年 | 95篇 |
2002年 | 72篇 |
2001年 | 42篇 |
2000年 | 54篇 |
1999年 | 36篇 |
1998年 | 21篇 |
1997年 | 20篇 |
1996年 | 13篇 |
1995年 | 15篇 |
1994年 | 14篇 |
1993年 | 13篇 |
1992年 | 15篇 |
1991年 | 22篇 |
1990年 | 18篇 |
1989年 | 18篇 |
1988年 | 17篇 |
1987年 | 16篇 |
1986年 | 13篇 |
1985年 | 14篇 |
1984年 | 7篇 |
1982年 | 8篇 |
1981年 | 12篇 |
1980年 | 8篇 |
1979年 | 10篇 |
1972年 | 10篇 |
1971年 | 8篇 |
1969年 | 6篇 |
1968年 | 9篇 |
1966年 | 8篇 |
1965年 | 10篇 |
排序方式: 共有4434条查询结果,搜索用时 15 毫秒
991.
The clinical presentation of multiple sclerosis (MS) with psychiatric symptoms is uncommon but it is believed that MS patients are twice as likely to be afflicted with bipolar disorder as the general population. We report two cases (mother and daughter) of MS presenting with bipolar disorder in the form of recurrent manic psychosis and whose outcome was favourable with neuroleptics and corticosteroids. In both cases we found multiple hypersignal lesions on brain magnetic resonance imaging (MRI), especially in the right frontal lobe where we observed signs of activity. Apart from clinical and radiological concordance, the patients exhibited similar class I HLA alleles and identical class II HLA alleles. We focused discussion on whether there may be a common genetic susceptibility to both illnesses or whether MS caused psychiatric manifestations. The coincidence of psychiatric and neurological symptoms in most relapses supports the second hypothesis. 相似文献
992.
The aim of the present study was to identify cognitive functions affected by traumatic brain injury (TBI) and to verify the mechanism underlying cognitive impairment. More precisely, cognitive deficits following TBI can be considered as a consequence of (a) a speed processing deficit, that is a general slowing of perceptual, motor and cognitive subroutines; (b) an impairment of the Central Executive System of working memory (CES).Thirty-seven patients were submitted to a neuropsychological battery, aimed to evaluate different cognitive functions.Results showed severe deficits in speed processing, divided attention,working memory, executive functions and long term memory.Regression analyses, performed to test the two hypotheses, showed that the working memory deficit hypothesis is able to explain divided attention, executive functions and long term memory deficits more than speed processing hypothesis. 相似文献
993.
In three experiments we measured reaction times (RTs) and error rates in identifying the global structure of spatially filtered stimuli whose spatial-frequency content was selected by means of three types of 2-D isotropic filters (Butterworth of order 2, Butterworth of order 10, and a filters with total or partial Gaussian spectral profile). In each experiment, low-pass (LP), bandpass (BP), and high-pass (HP) filtered stimuli, with nine centre or cut-off spatial frequencies, were used. Irrespective of the type of filter, the experimental results showed that: (a) RTs to stimuli with low spatial frequencies were shorter than those to stimuli with medium or high spatial frequencies, (b) RTs to LP filtered stimuli were nearly constant, but they increased in a nonmonotonic way with the filter centre spatial frequency in BP filtered stimuli and with the filter cut-off frequency in HP filtered stimuli, and (c) the identification of the global pattern occurred with all visible stimuli used, including BP and HP images without low spatial frequencies. To remove the possible influence of the energy, a fourth experiment was conducted with Gaussian filtered stimuli of equal contrast power (c(rms) = 0.065). Similar results to those described above were found for stimuli with spatial-frequency content higher than 2 cycles deg(-1). A model of isotropic first-order visual channels collecting the stimulus spectral energy in all orientations explains the RT data. A subsequent second-order nonlinear amplitude demodulation process, applied to the output of the most energetic first-order channel, could explain the perception of global structure of each spatially filtered stimulus, including images lacking low spatial frequencies. 相似文献
994.
We present an illusory display in which a grid of outlined squares is positioned in front of a moving luminance gradient. Observers perceive a strong, illusory, 'wavelike' motion of the superimposed squares. We compared luminance effects on dynamic and static aspects of this illusion. The dynamic aspect was investigated by means of a temporal gradient, which induced an illusory pulsing of the outlined squares. The static aspect was investigated in two different ways. In one experiment, the outlined squares were positioned on a spatial gradient, which caused the squares to look like trapezoid shapes. In another experiment, the squares were positioned on different luminance fields, which affected their apparent size. In all experiments, luminance settings were the same, and observers were asked to indicate the direction and strength of the induced distortions. The overall results show large agreements between the dynamic distortion and the first-mentioned static distortion, whereas different tendencies emerged for the second static distortion. In a second series of experiments, we examined these distortions for various ranges of the luminance gradient and for border gradients as well. On the basis of these data, we explored how the directions of the perceived distortions of the single-gradient displays examined in this paper could be related to each other. 相似文献
995.
Kristjánsson A 《Perception》2006,35(7):865-881
Recent results have suggested that the operational units of visual short-term memory (VSTM) are whole objects, rather than features or the total amount of information to be remembered. Here, for the first time, the influence of surface assignment on object formation for VSTM was investigated. The observers had to memorize the features of four briefly presented (300 ms) two-part objects, followed by a mask and a cue indicating which object to report on. The experiments contrasted whether there were any apparent depth differences between the two parts of each object, and whether observers had to report on only one or both features of the post-cued target object. Depth differences induced with stereoscopic disparity, and with a pictorial depth cue (simple interposition of object features), interfered strongly with performance when both features of an object needed to be memorized, but aided performance when only a single feature needed to be remembered. Furthermore, there was considerable within-feature interference consistent with some previous findings, but contradicting others. The potential implications for conceptions of VSTM are discussed in the light of two hypothesized stages: an early feature-based stage, as well as a higher-level object-based stage where the depth manipulations exert their effects. The results argue for a strong modulatory influence of surface assignment on object formation for a VSTM task. 相似文献
996.
Jiménez L Vaquero JM Lupiáñez J 《Journal of experimental psychology. Learning, memory, and cognition》2006,32(3):475-490
Four experiments investigate the differences between implicit and explicit sequence learning concerning their resilience to structural and superficial task changes. A superficial change that embedded the SRT task in the context of a selection task, while maintaining the sequence, did selectively hinder the expression of implicit learning. In contrast, a manipulation that maintained the task surface, but decreased the sequence validity, affected the expression of learning specifically when it was explicit. These results are discussed in the context of a dynamic framework (Cleeremans & Jiménez, 2002), which assumes that implicit knowledge is specially affected by contextual factors and that, as knowledge becomes explicit, it allows for the development of relevant metaknowledge that modulates the expression of explicit knowledge. 相似文献
997.
The aim of the present study is to determine patterns and personality disorder in subjects under cocaine dependence treatment using MCMI-II, and their relationship with sociodemographic variables and consumption characteristics. We assess 102 subjects under cocaine dependence treatment in Drug Abuse Centers in Galicia (Spain). The results indicate that the most prevalent basic scales of personality are the passive-aggressive, antisocial, narcisism and histrionic. Borderline and paranoid scales are the most prevalent with regard to the pathological personality scales. These results coincide with other international and national studies. We conclude pointing out the necessity to carry out studies with wider cocaine dependence samples in treatment, and the specific inclusion criteria should be established in the study. We also indicate the importance of carrying out a previous assessment of all demanding treatment subjects to design the objectives of the mentioned treatment. 相似文献
998.
In Experiment 1, the effect of the administration of the antidepressant amitriptyline (30 mg/kg) for 21 days on the acquisition and consolidation of the inhibitory avoidance task was studied in male and female mice. In Experiment 2, it was evaluated whether amitriptyline administered after the consolidation of this task would block the memory retrieval. Anxiety and spontaneous activity in the elevated plus maze were also assessed. When amitriptyline was given before the training phase of inhibitory avoidance it blocked learning in males and there was a tendency in the same direction in females. However, the drug administered between training and test phases did not affect conditioning. These effects of amitriptyline seem to be independent of its actions on anxiety and locomotor activity. It may be that the effects observed are related to the therapeutic effects of antidepressants. 相似文献
999.
The purpose of this research was to develop a new Sexual Attraction Questionnaire (SAQ) [Cuestionario de Atracción Sexual, CAS]. The goal was to determine whether sexual attraction could be represented as two different clusters (Attraction to men and Attraction to women), which would imply two negatively correlated factors or a bipolar one. Three studies were carried out with 182, 118, and 425 participants, respectively. Cluster and exploratory factor analyses were performed. The results obtained show satisfactory psychometric properties for the SAQ, the two clusters, and the two predicted negatively related factors or the bipolar factor. Results are discussed in the context of the different conceptions of sexual attraction and the fourfold typology: attracted to both sexes, to men, to women, or to neither sex. 相似文献
1000.
Infrahumanization researchs have shown that people attribute their ingroup exclusively human features, for example, the ability to experience secondary emotions. This bias lead people to deny this ability to outgroup and, consequently, to infrahumanize them. However, it would have conditions in which the infrahumanization is intensified. The aim of this study is to determine if there are characteristics in a threatening situation that influence in the level in which ingroup infrahumanize the outgroup. Two histories were constructed; in them, the outgroup committed a violent action against the ingroup, and as the degree of certainty about the perpetration, so the level of empathy with the victim were manipulated. The results show that when there are empathy with the victim and ambiguity about the perpetration, the infrahumanization to outgroup is higher. 相似文献