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J M Stern S K Johnson 《Journal of comparative psychology (Washington, D.C. : 1983)》1989,103(3):269-280
Prior to assuming the upright crouching posture over their pups during nursing bouts, lactating rats typically engage in several oral behaviors, including nuzzling, licking and rearranging pups. By acutely depriving dams of various aspects of perioral stimulation from pups (with anesthesia of the mystacial pads or of the tongue, with mouth suturing, or with muzzling), we found the following: (1) Distal stimulation from pups maintains proximity-seeking behavior, but is insufficient to stimulate nursing behavior. (2) Lack of tongue feedback decreases pup licking and hastens the onset of crouching. (3) Snout, but not tongue, contact with pups is required for hovering over them. (4) The position of the dam while hovering over her litter enables the pups to gain access to her ventrum, thereby provoking her upright, crouching posture. (5) Older pups are capable of bypassing the dam's perioral attentions and stimulating crouching directly by burrowing under the dam's ventrum. 相似文献
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In comparative anatomical studies of the shoulder, the humeral retractors are often grouped together as propulsive muscles, which are important in the propulsive stroke of the forelimb during quadrupedal locomotion. Electromyographic (EMG) analyses of these muscles in opossums, cats, and dogs in general have confirmed such conclusions. An EMG study of chimpanzee shoulder muscles during knuckle-walking found, however, that the humeral retractors are either inactive or perform a function unrelated to propulsion (Larson & Stern, 1987). This contrast in muscle recruitment patterns between chimpanzees and more "typical" mammalian quadrupeds was attributed to the derived morphology of the chimpanzee shoulder. The present study examines the activity patterns of the humeral retractors in the vervet monkey, a primate more closely resembling nonprimate mammals in its shoulder morphology. The results of this EMG analysis show that despite the significant differences in anatomy between chimpanzees and vervets, the two species display very similar muscle recruitment patterns during quadrupedalism, and there is evidence for this same pattern in other species of primates. These differences in muscle activity patterns between primates and nonprimate mammals may be related to changes in the neurological control of locomotion in primates due to the evolutionary development of manipulative abilities in the primate forelimb. 相似文献
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Cindy D. Stern 《Synthese》1993,95(3):379-418
A shift in emphasis can change the truth-value of a singular causal sentence. This poses a challenge to the view that singular sentences predicate a relation. I argue that emphasized causal sentences conjoin predication of a causal relation between events with predication of a relation of causal relevance between states of affairs (or perhaps facts). This is superior to the treatments of such sentences offered by Achinstein, Dretske, Kim, Sanford, Bennett, and Levin. My proposal affords clarity regarding logical structure, at least at a certain level of detail. It makes the relation between the content of an emphasized causal sentence and the unemphasized version clear. It answers some questions about the ontological requirements of the truth of emphasized causal sentences, without introducing new entities (as do some other accounts) or unacceptable consequences for identity and individuation of events. 相似文献
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J M Kolunie J M Stern 《Journal of comparative psychology (Washington, D.C. : 1983)》1990,104(4):352-360
Role of perioral somatosensation in the display of maternal aggression in Long-Evans Norway rats (Rattus norvegicus) was investigated during early lactation by local anesthesia of the mystacial pads with lidocaine, which blocks conduction in the infraorbital nerve. Acute perioral anesthesia markedly reduced the likelihood that maternal aggression was expressed; this effect of perioral anesthesia was not ameliorated by a repeated test with the same treatment or by pretreatment fighting experience. The dams that fought with the intruder during perioral anesthesia did so after greatly increased sniffing contact and with decreased vigor compared with controls. Males that were attacked tended to freeze, whereas males that were not attacked were active. Thus, trigeminal afferents are critical for the initiation and normal execution of maternal aggression responses in Norway rats. 相似文献
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We examined Milgram’s (1977) lost-letter technique using e-mail. In the first experiment, 79 college faculty received mock lost e-mail messages. Nineteen percent of those who received the messages responded, in all cases by returning the message to the “sender” instead of forwarding it to the “recipient.” In the second study, attitudes toward presidential candidate Ross Perot were examined by sending out two different messages to 200 randomly selected e-mail addresses in the United States. Although there was no differential response rate, examination of content revealed attitudes consistent with concurrent poll data. 相似文献
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This experiment studies French-speaking adults' preferences for prosodic marking (focal accent) or morphosyntactic marking (clefting) to express information contrasts in dialogue. Our goal is to determine what syntactic and conceptual factors might contribute to these preferences, by examining for the former, the grammatical function of the item bearing the contrastive mark (subject vs complement) and, for the latter, the size of the class to which the contrasted item belongs (two members vs more than two members). The subjects' responses on a forced-choice judgment task showed that when only one device was used for contrast, subjects clearly preferred clefting for grammatical subjects and focal accent for complements. When both devices were used (prosodic and morphosyntactic), contrasted subjects were preferred over contrasted complements. Response times were longer when the contrasted item belonged to a two-member class. These results demonstrate that subjects' judgments of the suitability of linguistic devices for expressing information contrasts in French are more highly affected by syntactic factors than conceptual ones. 相似文献