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Effects of differences between stimuli, responses, and reinforcer rates on conditional discrimination performance 总被引:5,自引:5,他引:0
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In a discrete-trial conditional discrimination procedure, 4 pigeons obtained food reinforcers by pecking a key with a short latency on trials signaled by one stimulus and by pecking the same key with a long latency on trials signaled by a second stimulus. The physical difference between the two stimuli and the temporal separation between the latency values required for reinforcement were varied factorially over four sets of conditions, and the ratio of reinforcer rates for short and long latencies was varied within each set of conditions. Stimulus discrimination varied directly with both stimulus and response differences and was unaffected by the reinforcer ratio. Sensitivity to reinforcement, estimated by generalized-matching-law fits to the data within each set of conditions, varied directly with the response difference but inversely with the stimulus difference arranged between sets of conditions. Because variations in stimulus differences, response differences, and reinforcer differences did not have equivalent effects, these findings question the functional equivalence of the three terms of the discriminated operant: antecedent stimuli, behavior, and consequences. 相似文献
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The focus of the present study was on the intersegmental relationships that emerge when both task and oganismic constraints are imposed upon the coordination system. Seven right-handed subjects were required to reach and grasp a cup (hand transport phase) and place it on a designated target (cup transport phase), using either their preferred or nonpreferred hand. The kinematics of the movement were examined as a function of task (grasping a full cup versus grasping an empty one) and organismic (preferred or nonpreferred hand) constraints. During the hand transport phase, a task constraint effect was revealed through an increase in the low-velocity phase for the full cup condition. This constraint coexisted with a decrease in angular motion of the shoulder and elbow joints, indicating subjects reduced the number of variables to be independently controlled in the final homing-in stage of the movement. Accompanying this decrease in angular change was an increase in the displacement of the trunk. During the cup transport phase, the trunk was shown to contribute significantly more to the movement in the full cup condition and for the left hand movements, thereby increasing the stability of the movement system. These findings are in agreement with Bernstein's (1967) notion of fixating parts of the body as an initial solution to a movement problem, and they lend support to the concept of a proximodistal organization of coordination. 相似文献
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Lozoff B Park AM Radan AE Wolf AW 《International journal of behavioral development》1995,18(2):277-295
It has been established through several decades of research that children's home environments significantly influence their development. Many researchers have also been interested in expanding research beyond indirect measures of the home environment, such as socioeconomic status, to help understand the nature of specific environmental mechanisms which influence early behavior and cognitive development. The Home Observation for Measurement of the Environment (HOME) Inventory was developed to meet these needs. Specifically, HOME measures the quality of stimulation in a child's early family environment. Almost all studies of the approach's reliability and validity have been conducted with US samples. HOME is, however, being used in other countries. The authors report their findings from a study of whether the psychometric properties of HOME based upon US samples parallel those found in Costa Rica, and whether HOME discriminates between Costa Rican environments with different associations to child health and development. Focus centers upon the infant/toddler version of the HOME Inventory. HOME data for 183 healthy Costa Rican infants were compared to the original HOME standardization sample from Little Rock, Arkansas. The study found the HOME Inventory to be helpful in identifying children at risk for delayed development in this Latin American sample. Lower HOME scores related to a shorter duration of breastfeeding and differentiated children with iron deficiency anemia in infancy, a condition associated with long-lasting developmental disadvantage. 相似文献
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医学人类学是医学与人类学相交织的一门边缘学科,它主要涉及健康、疾病及医疗中与文化相关联的内容。医学人类学的研究领域包括:跨文化医疗系统(如不同民族、不同历史之间)的比较研究,与人类学有关的营养、人口、出生、年龄、药物滥用、社会流行病学等问题,以及人种心理学、生物医学的文化分析,还包含古病理学和疾病人种历史学研究及临床应用人类学。 相似文献
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2001年的科学哲学 总被引:1,自引:0,他引:1
一种民主制度的最重要也是讨论最少的任务之一就是要保护它的成员免遭这种制度中的意识形态的伤害.必须正确地看待所有的意识形态.人们必须把它们当作神话故事来看待,它们能告诉人很多有趣的事,但也包含了很多谬误和令人生厌的谎言.当人们按照某一观点行动时,他们的态度也应该像密探一样,为了在一个陌生的国家里获得成功而采纳它的信仰并在细枝末节上按照这些信仰去做,但并不全盘接受.这一点适用于所有的信仰,适用于基督教上帝的存在这一信仰,适用于所有的人生来平等的信仰,也适用于科学.那么,这是否是一种陌生和荒谬的态度呢?科学当然总是处在与权威主义和迷信战斗的前沿.相对于宗教信仰而言,我们有了越来越大的思想自由,这应当归功于科学;人类从古代的僵硬思维方式中解放出来,也应当归功于科学.今天,这些思维方式仅仅是一些糟糕的 相似文献
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