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931.
Hebbian learning is a biologically plausible and ecologically valid learning mechanism. In Hebbian learning, 'units that fire together, wire together'. Such learning may occur at the neural level in terms of long-term potentiation (LTP) and long-term depression (LTD). Many features of Hebbian learning are relevant to developmental theorizing, including its self-organizing nature and its ability to extract statistical regularities from the environment. Hebbian learning mechanisms may also play an important role in critical periods during development, and in a number of other developmental phenomena. 相似文献
932.
The concept of informed consent was one of the most fruitful ideas that deeply changed the relationships between physicians
and their patients from paternalism to respect for the personal autonomy of subjects needing professional medical care. The
great progress in medicine, also involving the pharmaceutical industry, has created an increasing need to perform different
clinical and experimental trials. The evolution of clinical research in the last decades has influenced strongly the design
of these studies. One of the most important changes in this field has been the use of placebo groups in double-blind controlled
studies. The controversies have involved not only the use of placebo when standard or proven treatment was available, but
also some specific problems concerning the procedure of obtaining informed consent in such trials. This paper briefly presents
the evolution of informed consent in Poland as well as different ethical and legal problems concerning informed consent and
the use of placebo controls in clinical trials.
An earlier version of this paper was presented at an international conference, “Placebo: Its Action and Place in Health Research
Today,” held in Warsaw, Poland on 12–13 April, 2003. 相似文献
933.
Sleep is crucial to the 'off-line' consolidation of procedural memory. A recent study by Robertson et al. shows that this might hold true only if the task is trained explicitly, that is, with the subject being aware of the task structure. These new data add to emerging evidence that sleep-related memory consolidation involves an interaction between different memory systems. 相似文献
934.
Neurophysiological experiments with monkeys have demonstrated that working memory (WM) is associated with persistent neural
activity in multiple brain regions, such as the prefrontal cortex (PFC), the parietal cortex, and posterior unimodal association
areas. WM maintenance is believed to require the coordination of these brain regions, which do not function in isolation but,
rather, interact to maintain visual percepts that are no longer present in the environment. However, single-unit physiology
studies and traditional univariate analyses of functional brain imaging data cannot evaluate interactions between distant
brain regions, and so evidence of regional integration during WM maintenance is largely indirect. In this study, we utilized
a recently developed multivariate analysis method that allows us to explore functional connectivity between brain regions
during the distinct stages of a delayed face recognition task. To characterize the neural network mediating the on-line maintenance
of faces, the fusiform face area (FFA) was defined as a seed and was then used to generate whole-brain correlation maps. A
random effects analysis of the correlation data revealed a network of brain regions exhibiting significant correlations with
the FFA seed during the WM delay period. This maintenance network included the dorsolateral and ventrolateral PFC, the premotor
cortex, the intraparietal sulcus, the caudate nucleus, the thalamus, the hippocampus, and occipitotemporal regions. These
findings support the notion that the coordinated functional interaction between nodes of a widely distributed network underlies
the active maintenance of a perceptual representation. 相似文献
935.
Fischer H Fransson P Wright CI Bäckman L 《Cognitive, affective & behavioral neuroscience》2004,4(3):326-334
Blood-oxygenation-level-dependent signal was measured with functional magnetic resonance imaging in 24 healthy young subjects
(12 men and 12 women) during viewing of angry, fearful, and neutral male and female face pictures. Exposure to angry male
as opposed to angry female faces activated the visual cortex and the anterior cingulate gyrus significantly more in men than
in women. A similar sex-differential brain activation pattern was present during exposure to fearful but not neutral faces.
Previous behavioral studies indicate enhanced physiological arousal in men but not in women during exposure to angry male
as opposed to female faces, and brain imaging studies have shown that the occipital cortex and the anterior cingulate gyrus
are influenced by activity in the autonomic nervous system as well as by visual attention. Hence, we suggest that the elevated
occipital and anterior cingulate activation in men during confrontation with other angry and fearful males may reflect enhanced
vigilance in a potentially dangerous situation. 相似文献
936.
Koster EH Crombez G Van Damme S Verschuere B De Houwer J 《Emotion (Washington, D.C.)》2004,4(3):312-317
According to models of attention and emotion, threat captures and holds attention. In behavioral tasks, robust evidence has been found for attentional holding but not for attentional capture by threat. An important explanation for the absence of attentional capture effects is that the visual stimuli used posed no genuine threat. The present study investigated whether visual cues that signal an aversive white noise can elicit attentional capture and holding effects. Cues presented in an attentional task were simultaneously provided with a threat value through an aversive conditioning procedure. Response latencies showed that threatening cues captured and held attention. These results support recent views on attention to threat, proposing that imminent threat captures attention in everyone. 相似文献
937.
Harmon-Jones E Vaughn-Scott K Mohr S Sigelman J Harmon-Jones C 《Emotion (Washington, D.C.)》2004,4(1):95-101
The present research extended past research demonstrating that approach-motivated anger is associated with greater left than right frontal cortical activity. Because past research had examined difference scores between left and right frontal activity, it was unable to test whether approach-motivated anger increased left activity, decreased right activity, or both. In addition, the present research examined a potential moderator of the effect of insult on left frontal activity. That is, it tested whether sympathy for an insulting person would reduce the left frontal activity that occurs following being insulted. Results indicated that left frontal activity was increased and right frontal activity was decreased by the insult. Moreover, these effects were inhibited when high levels of sympathy were first aroused. 相似文献
938.
As the Internet has changed communication, commerce, and the distribution of information, so too it is changing psychological research. Psychologists can observe new or rare phenomena online and can do research on traditional psychological topics more efficiently, enabling them to expand the scale and scope of their research. Yet these opportunities entail risk both to research quality and to human subjects. Internet research is inherently no more risky than traditional observational, survey, or experimental methods. Yet the risks and safeguards against them will differ from those characterizing traditional research and will themselves change over time. This article describes some benefits and challenges of conducting psychological research via the Internet and offers recommendations to both researchers and institutional review boards for dealing with them. ((c) 2004 APA, all rights reserved) 相似文献
939.
The relationship between acute stress disorder and posttraumatic stress disorder in severely injured trauma survivors 总被引:4,自引:0,他引:4
This prospective longitudinal study was designed to investigate the relationship between acute stress disorder (ASD) and the subsequent development of posttraumatic stress disorder (PTSD) in a population of severely injured hospitalised trauma survivors. Symptoms of ASD were assessed just prior to discharge in 307 consecutive admissions to a Level 1 Trauma Centre, with PTSD assessments completed at 3 and 12 months post-injury. A well-established structured clinical interview was adopted for both assessments. Only 1% of the sample met criteria for an ASD diagnosis (at a mean of 8 days post-injury), while the incidence of PTSD was 9% at 3 months and 10% at 12 months. Although all ASD symptom clusters contributed to the prediction of subsequent PTSD severity, logistic regression indicated that only re-experiencing and arousal predicted a categorical PTSD diagnosis. The dissociative symptoms that form the core of ASD were rarely endorsed and showed high specificity but low sensitivity, resulting in a high proportion of false negative diagnoses. Reducing the number of dissociative symptoms required for a diagnosis ameliorated, but did not resolve, the problem. In this particular population, the low sensitivity of the ASD diagnosis renders it a poor screening test for use in identifying high risk individuals for early intervention and prevention strategies. 相似文献
940.