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51.
The associative relation underlying autoshaping in the pigeon   总被引:4,自引:4,他引:0       下载免费PDF全文
Fifteen pigeons were exposed to either response-independent or response-dependent schedules of water reinforcement, whereby water was injected directly into the unrestrained pigeons' mandibles. Key-contact responses were released by a lighted key correlated with water, but not by a lighted key uncorrelated with water. A negative response-reinforcer contingency suppressed autoshaped key-contact responses, resulting in responding directed away from the lighted key. In all pigeons, water injected directly into the mandibles elicited a consummatory fixed-action pattern of “mumbling” and swallowing. The lighted key correlated with water released a broader set of both appetitive and consummatory responses: approach to the lighted key, “bowing”, “rooting”, “mumbling”, and swallowing. Key-contact responses were “rooting” and “mumbling” motions of the beak on the surface of the key. Views of autoshaping based on stimulus substitution or stimulus surrogation do not fully explain the origin of autoshaped responses not previously elicited by the reinforcer. The present findings are consonant with views of conditioning that emphasize the large degree of biological pre-organization in conditioned response patterns, and the importance of associative factors in the control of such patterns.  相似文献   
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The joint control of rate of key pecking in pigeons by stimulus-reinforcer and response-reinforcer relationships was studied in the context of a two-component multiple schedule of reinforcement. Food presentation was always associated with one component and extinction with the other. The stimulus-reinforcer relationship was manipulated by varying the relative durations of the two components. In the food-presentation component, a fixed rate of reinforcement, independent of rate of responding, was generated by a schedule referred to as “T*”. One aspect of the response-reinforcer relationship, contiguity, was manipulated by varying the percentage of delayed reinforcers. With the multiple T* extinction schedule, stimulus-reinforcer and response-reinforcer relationships could be varied independently of one another. Rate of key pecking was sensitive to manipulations of both relationships. However, significant differential effects due to either the stimulus-reinforcer or response-reinforcer relationship were obtained only when the other relationship was weak: stimulus-reinforcer and response-reinforcer relationships interacted in the joint control of responding.  相似文献   
53.
Communication about the location of a hidden incentive was studied in chimpanzee-human dyads, in which each member of a pair served alternately as “sender” and “recipient” of information. When the human cooperated with the chimpanzee in finding the goal, from the very beginning the chimpanzees were able to produce and comprehend behavioral cues which conveyed accurate locational information. When the human and chimpanzee competed for the goal, the chimpanzees learned both to withhold information or mislead the recipient, and to discount or controvert the sender's own misleading cues. The chimpanzee's ability to convey and utilize both accurate and misleading information, by taking into account the nature of the sender or recipient, provides evidence of a capacity for intentional communication in this nonhuman primate species.  相似文献   
54.
Intervocalic intervals (IVI) from the contextual fluent speech of 14 stutterers and controls were examined at one-quarter speed on simultaneously prepared spectrograms and intensity x time displays. Seven subsegments within the IVI were identified and their durations compared between the two groups. Stutterers were slower than controls in transitional subsegments, corresponding to movements of the tongue and larynx, but not in steady-state subsegments. The results are interpreted as suggesting that stutterers are not able to move their laryngeal and supralaryngeal structures as quickly as nonstutterers.  相似文献   
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Oncofertility is one of the 9 NIH Roadmap Initiatives, federal grants intended to explore previously intractable questions, and it describes a new field that exists in the liminal space between cancer treatment and its sequelae, IVF clinics and their yearning, and basic research in cell growth, biomaterials, and reproductive science and its tempting promises. Cancer diagnoses, which were once thought universally fatal, now often entail management of a chronic disease. Yet the therapies are rigorous, must start immediately, and in many cases result in premature failure of the body's reproductive ability. In women, this loss is especially poignant; unlike the routine storage of sperm, which is done in men and boys facing similar treatment decisions, freezing oocytes in anticipation of fertility loss is not possible in most cases, and creating an embryo within days of diagnosis raises significant moral, social and medical challenges. Oncofertility is the study of how to harvest ovarian tissue in women facing cancer to preserve their gametes for future use with IVF, thus allowing the decisions about childbearing to be deferred and reproductive choices to be preserved. The research endeavor uses the capacity of the ovarian follicle to produce eggs in vitro. Developing the human follicle to ovulate successfully outside the body is scientifically difficult and ethically challenging. Infertility is linked to long-standing religious and moral traditions, and is intertwined with deeply contentious social narratives about women, families, illness and birth. Is the research morally permissible? Perhaps imperative if understood as a repair from iatrogenic harms? How are considerations of justice central to the work? How will vulnerable subjects be protected? What are the moral implications of the work for women, children and families? What are the implications for society if women could store ovarian tissue as a way of stopping the biological clock? What are the moral possibilities and challenges if eggs can be produced in large quantities from a stored ovarian tissue?  相似文献   
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The objective was to describe weight concerns, dieting, and meal skipping of adolescents and to determine associations with the Healthy Eating Index-C (HEI-C). Data, that were collected using the Food Behaviour Questionnaire, revealed that participants (male=810, female=1016) in grades 9/10 reported weight concerns (n=518), dieting (n=364), and skipping breakfast (n=498), lunch (n=252), and/or dinner (n=129). Of those dieting or weight concerned (n=602), 61% were healthy weight and of those not dieting or weight concerned (n=1224), 13% were overweight/obese. The ordinal logistic regression analysis revealed that HEI-C was likely to be rated lower among those weight concerned and dieting (p<.001), and among those that skipped the breakfast meal (p<.001). The current study identified inappropriate weight concerns and dieting that compromised diet quality and has implications for future intervention and policy development.  相似文献   
60.
Paul Woodruff 《Topoi》2011,30(2):151-155
The paper seeks to identify criteria that digital communication would have to satisfy in order to serve the functions for which theater is necessary in human cultures.  相似文献   
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