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51.
ABSTRACT Tests which predict the sex of a fetus have led to female feticide in India, and hence to demands that such tests be banned. This paper examines the arguments for banning such tests. These will depend partly on one's views regarding the morality of feticide: different views are discussed. However the morality of feticide is not the only relevant consideration, especially since it may become possible to choose the sex of the child at conception. Whether or not parents have the right to freedom of choice and information is analysed. Many non-western societies have special problems since the strong preference for boys may lead to the neglect of female children and to female infanticide. In heavily populated countries like India and China the need to control population growth is an additional complication. The paper concludes that in these societies the case for banning tests is weak.  相似文献   
52.
Increased use of online communication in everyday life presents a growing need to understand how people are influenced by others in such settings. In this study, online comments established social norms that directly influenced readers' expressions of prejudice both consciously and unconsciously. Participants read an online article and were then exposed to antiprejudiced or prejudiced comments allegedly posted by other users. Results revealed that exposure to prejudiced (relative to antiprejudiced) comments influenced respondents to post more prejudiced comments themselves. In addition, these effects generalized to participants' unconscious and conscious attitudes toward the target group once offline. These findings suggest that simple exposure to social information can impact our attitudes and behavior, suggesting potential avenues for social change in online environments.  相似文献   
53.
Many of the policy choices we face that have implications for the lives of future generations involve creating a risk that they will live lives that are significantly compromised. I argue that we can fruitfully make use of the resources of Scanlon’s contractualist account of moral reasoning to make sense of the intuitive idea that, in many cases, the objection to adopting a policy that puts the interest of future generations at risk is that doing so wrongs those who will live in the further future.  相似文献   
54.
Conditioned behavior as observed during classical conditioning in a group of identically treated animals provides insights into the physiological process of learning and memory formation. However, several studies in vertebrates found a remarkable difference between the group-average behavioral performance and the behavioral characteristics of individual animals. Here, we analyzed a large number of data (1640 animals) on olfactory conditioning in the honeybee (Apis mellifera). The data acquired during absolute and differential classical conditioning differed with respect to the number of conditioning trials, the conditioned odors, the intertrial intervals, and the time of retention tests. We further investigated data in which animals were tested for spontaneous recovery from extinction. In all data sets we found that the gradually increasing group-average learning curve did not adequately represent the behavior of individual animals. Individual behavior was characterized by a rapid and stable acquisition of the conditioned response (CR), as well as by a rapid and stable cessation of the CR following unrewarded stimuli. In addition, we present and evaluate different model hypotheses on how honeybees form associations during classical conditioning by implementing a gradual learning process on the one hand and an all-or-none learning process on the other hand. In summary, our findings advise that individual behavior should be recognized as a meaningful predictor for the internal state of a honeybee--irrespective of the group-average behavioral performance.  相似文献   
55.
Different lines of evidence suggest that human immunodeficiency virus type 1 (HIV-1) infection is complicated by a variety of adverse effects on neuroendocrine systems. Soon after the discovery of HIV-1, reports began to appear suggesting that a number of neurotransmitter and neuroendocrine activities were negatively impacted by this infection. In 1987 it was observed that fine-needle aspiration of the lung in patients with acquired immunodeficiency syndrome resulted in syncopal reactions. Subsequently, an abnormality in the autonomic nervous system was reported in these patients. However, investigations in this area have remained limited due to the assumption that HIV-1-mediated activation of various endocrine systems was related to the major life stressor of living with a fatal disease. Evidence accumulated over the years has indicated, instead, that there are various other mechanisms in addition to life stressors that also play an important role in negatively impacting the neuroendocrine systems in this infection. This article examines various developments that have taken place in this area in order to provide avenues for future research.  相似文献   
56.
57.
Visual short-term memory for sequential arrays   总被引:3,自引:0,他引:3  
The capacity of visual short-term memory (VSTM) for a single visual display has been investigated in past research, but VSTM for multiple sequential arrays has been explored only recently. In this study, we investigate the capacity of VSTM across two sequential arrays separated by a variable stimulus onset asynchrony (SOA). VSTM for spatial locations (Experiment 1), colors (Experiments 2-4), orientations (Experiments 3 and 4), and conjunction of color and orientation (Experiment 4) were tested, with the SOA across the two sequential arrays varying from 100 to 1,500 msec. We find that VSTM for the trailing array is much better than VSTM for the leading array, but when averaged across the two arrays VSTM has a constant capacity independent of the SOA. We suggest that multiple displays compete for retention in VSTM and that separating information into two temporally discrete groups does not enhance the overall capacity of VSTM.  相似文献   
58.
Two dot arrays, each containing a different set of six randomly selected locations from a 5 × 5 matrix, were presented briefly and were separated by an interstimulus interval (ISI) of 0, 200, 500, or 1,500 msec. Subjects were asked to remember these locations and to report whether a probe dot matched the locations in memory. To find out whether the subjects had formed an integrated representation of the two arrays, the probe dot was accompanied by matrix elements from the first array, from the second array, or from both arrays. Memory for Array 1 was significantly impaired when the retrieval context was drawn from Array 2, and vice versa, suggesting that the two arrays were represented separately. This effect was observed only at an ISI of 500 msec or longer. We propose that as Array 1 is better consolidated, its representation becomes more separated from that of Array 2.  相似文献   
59.
Immediately after infection, Human immunodeficiency virus, type 1 (HIV-1) enters the central nervous system (CNS) and is localized in highest concentration in the hippocampus and basal ganglia. Since these areas are associated with HPA axis and autonomic activities as well as cognition, it has been hypothesized that these functions will be impacted adversely in HIV-1 infection. In the treatment of HIV infection, although the highly potent antiretroviral (HAART) drugs have been effective in reducing peripheral viral load and prolonging life expectancy, these drugs do not cross the blood-brain barrier in therapeutic concentrations. Therefore, it has been proposed that the beneficial effects of HAART on the CNS will be limited. Our investigations on seropositive individuals, showing hypo-reactivity of the autonomic system and HPA axis activity suggest that HIV-1 infection is a model of chronic stress. Furthermore, an elevated baseline TNF-alpha level as well as its increased reactivity to an alpha-adrenergic challenge among HIV-1+ individuals, may lead to additional neurodegeneration. It is proposed that the effects of HIV-1 infection on the brain will have implications for neurocognitive and mental health functioning in seropositive individuals even in patients undergoing HAART therapy. These outcomes may result in the need to develop facilities for long term "care-giving".  相似文献   
60.
Animal Cognition - Geophagy has been documented in different animal taxa including Aves and particularly in Passeriformes. However, no geophagic activity has been reported in the genus Turdoides of...  相似文献   
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