全文获取类型
收费全文 | 58748篇 |
免费 | 2082篇 |
国内免费 | 21篇 |
专业分类
60851篇 |
出版年
2019年 | 596篇 |
2018年 | 821篇 |
2017年 | 810篇 |
2016年 | 929篇 |
2015年 | 688篇 |
2014年 | 803篇 |
2013年 | 5029篇 |
2012年 | 1444篇 |
2011年 | 1485篇 |
2010年 | 961篇 |
2009年 | 941篇 |
2008年 | 1408篇 |
2007年 | 1252篇 |
2006年 | 1146篇 |
2005年 | 1041篇 |
2004年 | 992篇 |
2003年 | 1012篇 |
2002年 | 1003篇 |
2001年 | 1749篇 |
2000年 | 1681篇 |
1999年 | 1245篇 |
1998年 | 596篇 |
1996年 | 671篇 |
1995年 | 631篇 |
1994年 | 632篇 |
1992年 | 1272篇 |
1991年 | 1167篇 |
1990年 | 1168篇 |
1989年 | 1089篇 |
1988年 | 1048篇 |
1987年 | 1041篇 |
1986年 | 1063篇 |
1985年 | 1081篇 |
1984年 | 957篇 |
1983年 | 824篇 |
1982年 | 623篇 |
1981年 | 678篇 |
1979年 | 948篇 |
1978年 | 706篇 |
1976年 | 618篇 |
1975年 | 871篇 |
1974年 | 923篇 |
1973年 | 987篇 |
1972年 | 912篇 |
1971年 | 848篇 |
1970年 | 766篇 |
1969年 | 764篇 |
1968年 | 952篇 |
1967年 | 874篇 |
1966年 | 828篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
Deprivation and satiation: The interrelations between food and wheel running 总被引:2,自引:1,他引:1 下载免费PDF全文
Two experiments were designed to assess whether depriving rats of food would increase the reinforcement effectiveness of wheel running (Experiment 1) and whether satiation for wheel running would decrease the reinforcement effectiveness of food (Experiment 2). In Experiment 1, a progressive-ratio schedule was used to measure the reinforcement effectiveness of wheel running when rats were deprived or not deprived of food. Completion of a fixed number of lever presses released a brake on a running wheel for 60 s, and the response requirement was systematically increased until the rat stopped pressing or until 8 hr had elapsed. The ratio value reached (and the total number of lever presses) was an inverted-U function of food deprivation (percentage body weight). In Experiment 2, when wheel running preceded test sessions, fewer food-reinforced lever presses were maintained by the progressive-ratio schedule, and responding occurred at a lower rate on a variable-interval schedule. An interpretation of these results is that deprivation or satiation with respect to one event (such as food) alters the reinforcement effectiveness of a different event (such as access to wheel running). 相似文献
962.
It is suggested that molar streams of behavior are constructed of various arrangements of three elementary constituents (elicited, evoked, and emitted response classes). An eight-cell taxonomy is elaborated as a framework for analyzing and synthesizing complex behavioral repertoires based on these functional units. It is proposed that the local force binding functional units into a smoothly articulated kinetic sequence arises from temporally arranged relative response probability relationships. Behavioral integration is thought to reflect the joint influence of the organism's hierarchy of relative response probabilities, fluctuating biological states, and the arrangement of environmental and behavioral events in time. 相似文献
963.
Relationship between Knapp's metaphor scale of attitudes toward time and subjective estimation of fixed time intervals, measured by a modification of Lovett Doust's method, was described. Results were discussed within the framework of studies relating the measurements of cognitive styles and altered consciousness states to the dilated or accelerated perceptions of time. 相似文献
964.
V D Lutzer 《Perceptual and motor skills》1986,62(3):959-966
A match-to-sample task and a preference-ranking procedure were used to provide predifferentiation experiences on a color discrimination for 6- and 8-yr.-old children. The subjects included an educable mentally retarded 8-yr.-old group, an average 8-yr.-old group, a gifted 6-yr.-old group, and an average 6-yr.-old group. Mental age was the best predictor of success on task. A significant interaction of sex and teaching method suggests an advantage of girls in this group in instructional situations in which the perceptual learning task and testing tasks are not exactly the same. Girls did better than boys when a different response for task content was required in testing from that in teaching. Boys and girls performed similarly when the training task was the same as the testing task. 相似文献
965.
Relationships between experiences, processing style, and sex-related differences in performance on spatial tests 总被引:1,自引:0,他引:1
53 female and 45 male undergraduates were administered the Spatial Antecedents Questionnaire (Activities, Academic Courses, Self-assessments, and Environmental Mapping subscales), the Spatial Dimensionality Test (Embedded Figures, Card Rotations, Paper Folding, Surface Development, Horizontal/Vertical Rotations, and Cube Perspectives subtests), and Revised-Individual Differences Questionnaire of Paivio. Scores from the Academic Courses and Self-assessment scales accounted for the most variability in spatial performance. Visual processing style correlated with performance on spatial tests for men, but not for women. Different patterns of activities and experiences correlated with spatial test performance for men and women. 相似文献
966.
A laboratory and a field study investigated the biasing effects of subordinate likableness on leaders' attributions for subordinate poor performance and their corrective actions toward subordinates. In the laboratory study, 96 undergraduate students served as leaders and were presented with a vignette describing an incident of poor performance committed by either a liked or a disliked subordinate. Leaders made attributions for the poor performance and then rated the appropriateness of a series of corrective actions. Analyses revealed that leaders made similar attributions for the poor performance of liked and disliked subordinates, but were more inclined to punish a disliked subordinate than a liked subordinate. A second study replicated these findings with 98 leaders in an actual organization. Implications of the results for disciplinary policies are discussed. 相似文献
967.
968.
With the Structured Psychopathological Evaluation-System (SPES) an instrument existed for employment of objective criteria. This study was designed to present an evaluation system based on new scientific results, that is applying on the strength of a reduced catalogue of symptoms (94 compared with 198 Items at SPES-A) to clinical routine. Additional findings differentiated by this system be able to classify by the help of an operational decision system. 相似文献
969.
295 expert opinans of the NVA (National People's Army) in conditions after craniocerebral traumas for which an EEG findings was present were subjected to an retrospective analysis to determine the importance of EEG for export opinion. In 59.3% of cases EEG was significant for expert opinion, but was of prime importance only in 1.3%. In 161 expert opinions the total damage of the body was determined. This gave the possibility of a statistical correlation of individual EEG findings with the extent of the body damage. Mean percentage values of the individual degrees of severity of EEG changes could be calculated on the basis of these data. The great importance of EEG for military medical opinion could also be confirmed in comparison with 8 other clinical data and findings. 相似文献
970.
G Sack H J Leubuscher B P?gelt N Roth 《Psychiatrie, Neurologie, und medizinische Psychologie》1986,38(5):246-254
The influence in 8 of our patients with ophthalmic migraine of photic driving with sine-like flashing lights on EEG background activity was checked and the visually evoked potentials following the application of diffused simple light stimuli were analyzed using the recovery cycle technique. The results indicate a slightly increased tonic activity of the structures of the mesencephalic formatio reticularis, such as may be produced by slight functional disturbances. Some vegetative secondary symptoms of migraine attacks and some of the changes in EEG observed in patients with ophthalmic migraine are explicable by such an abnormality. 相似文献