全文获取类型
收费全文 | 60380篇 |
免费 | 1148篇 |
国内免费 | 8篇 |
专业分类
61536篇 |
出版年
2020年 | 617篇 |
2019年 | 804篇 |
2018年 | 1088篇 |
2017年 | 1112篇 |
2016年 | 1170篇 |
2015年 | 821篇 |
2014年 | 974篇 |
2013年 | 4561篇 |
2012年 | 1742篇 |
2011年 | 1858篇 |
2010年 | 1180篇 |
2009年 | 1220篇 |
2008年 | 1616篇 |
2007年 | 1567篇 |
2006年 | 1423篇 |
2005年 | 1230篇 |
2004年 | 1170篇 |
2003年 | 1159篇 |
2002年 | 1131篇 |
2001年 | 2050篇 |
2000年 | 2005篇 |
1999年 | 1463篇 |
1998年 | 664篇 |
1997年 | 575篇 |
1995年 | 561篇 |
1992年 | 1216篇 |
1991年 | 1166篇 |
1990年 | 1139篇 |
1989年 | 1061篇 |
1988年 | 1027篇 |
1987年 | 976篇 |
1986年 | 939篇 |
1985年 | 1028篇 |
1984年 | 841篇 |
1983年 | 714篇 |
1982年 | 564篇 |
1979年 | 880篇 |
1978年 | 630篇 |
1977年 | 604篇 |
1976年 | 581篇 |
1975年 | 742篇 |
1974年 | 811篇 |
1973年 | 893篇 |
1972年 | 746篇 |
1971年 | 623篇 |
1970年 | 588篇 |
1969年 | 628篇 |
1968年 | 750篇 |
1967年 | 668篇 |
1966年 | 697篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Spatial coding in the processing of anaphor by good and poor readers: Evidence from eye movement analyses 总被引:1,自引:0,他引:1
Wayne S. Murray Alan Kennedy 《The Quarterly Journal of Experimental Psychology Section A: Human Experimental Psychology》1988,40(4):693-718
An experiment that examined the way in which young readers deployed eye movements while reading sentences and while answering questions containing either a pronominal or noun anaphor is reported. To evaluate the possible causal role played by differences in inspection strategies between readers of above- and below-average reading skill, a third“age control” group of younger children was also tested. This group was matched on absolute reading ability with the less skilled group of older children, and on relative reading ability (i.e. reading quotient) with the more skilled group. Differences in inspection strategy were apparent between the groups of good and poor readers. Good readers launched more selective reinspections, whereas the poorer readers were more inclined to engage in“backtracking” and appeared to make less use of the displayed text. In every case there was a marked similarity in the behaviour of the good readers and the“age controls”. These results suggest that the ability to code the spatial location of words in a sentence, and, where necessary, to use this information to launch accurately targetted selective reinspections of previously read text, plays a crucial role in the development of skilled reading performance. 相似文献
32.
Cyd C. Strauss Cynthia G. Last Michel Hersen Alan E. Kazdin 《Journal of abnormal child psychology》1988,16(1):57-68
The relationship between anxiety and depression was examined in a sample of 106 children and adolescents referred to an outpatient anxiety disorder clinic for children. Twenty-eight percent of patients with DSM-III diagnoses of anxiety disorders displayed a concurrent major depression. Children with anxiety disorders plus major depression were found (1) to be older, (2) to demonstrate more severe anxiety symptomatology, and (3) to be diagnosed with different rates of certain anxiety-disorder subtypes, when compared to anxious patients without major depression. Nondepressed anxious children and adolescents did not differ from a psychopathological control group in severity of either anxiety or depression symptoms. 相似文献
33.
The distorted room illusion (DRI) and the attendant argument for perceptual ambiguity is critically analyzed from a Gibsonian/ecological point of view. The notions of multiple specification, conflicting information, and perceptual skill are invoked in showing how the ecological approach can accommodate illusion effects that may remain under mobile binocular viewing conditions. Static optic arrays are shown not to be ambiguous. So-called equivalent configurations are found to be analytic artifacts, appearing when the problem of information is treated in geometrical terms without regard for constraints due to physical and ecological regularities. The relative importance of motion-based and motion-independent information is discussed. 相似文献
34.
Cyd C. Strauss Cynthia A. Lease Cynthia G. Last Greta Francis 《Journal of abnormal child psychology》1988,16(4):433-443
Differences between a clinical sample of younger (ages 5 to 11) and older (ages 12 to 19) children meeting DSM-III criteria for overanxious disorder (OAD) were examined. Younger and older children were compared in terms of (1) the rates of OAD diagnoses occurring in the two age groups, (2) sociodemographic characteristics, (3) symptom expression, (4) association with other forms of maladjustment, and (5) self-reported anxiety and depression. The prevalence of OAD diagnoses and sociodemographic characteristics did not differ. Although younger and older OAD children showed similar rates of most specific DSM-III OAD symptoms, older children presented with a higher total number of overanxious symptoms than younger children. Older children more frequently exhibited a concurrent major depression or simple phobia, whereas younger OAD children more commonly had coexisting separation anxiety or attention deficit disorders. Older OAD children reported significantly higher levels of anxiety and depression on self-report measures. Findings indicated that the expression of OAD varies by developmental level. 相似文献
35.
The development of the understanding of affective meaning in music was investigated. Subjects aged 4, 5, 6, and 19 assigned verbal labels to musical segments previously determined by adults to be representative of one of four affects (happy, sad, angry, afraid). Analysis of correct interpretations and errors revealed a pattern of interactions among age, sex, and affect indicating that the ability to verbalize an understanding of affective meaning in music consistent with that of adult subjects is present during the preschool years. Age-related similarities in performance, as well as differences favoring both younger and older subjects, were observed and were discussed in relation to recent research in, and theories of, affective development and communication.The authors thank H. Julia Hannay, Edward Kemery, Shiela MacDonald, and Robert McGrath for their assistance in this research. The conceptual inspiration of Joseph Intrieri is gratefully acknowledged. We also thank Leslie Brody, Robin Hornik, and several anonymous reviewers for their comments on an earlier draft of the paper. Portions of this research were presented at the Southeastern Conference on Human Development, Baltimore, April 1982. 相似文献
36.
37.
38.
Despite widespread popular belief in the activation of recurrent lesions in genital herpes simplex virus (HSV) by psychosocial stress, little empirical evidence supports that contention. This study retrospectively examined the role of stress in activation of HSV lesions as mediated by social support. Participants were 59 volunteers who had self-reported culture-positive genital HSV for at least 10 months. Measures of stress proneness (State-Trait Anxiety Inventory; STAI-Trait), recent stressful events (Schedule of Recent Events; SRE), and subjective appraisal of stress (global self-rating) were administered along with measures of general social support and herpes-specific social support. When retrospective reports of HSV symptoms were examined using a multiple-regression approach, duration of disease and amount of herpes-specific social support were found to be significant moderators of the relation between stress and number of HSV recurrences in the preceding 12 months. When duration of disease was short (less than 4 years), stress (SRE) and number of recurrences were positively associated; when disease duration was longer, there was no relationship. Similarly, at low levels of herpes-specific social support, a positive relation between stress (SRE) and number of recurrences was found. However, at higher levels of herpes-specific social support, no association was found. No relation was found between stress proneness (STAI-Trait) and HSV symptoms. However, subjective appraisal (global rating) of stress in the preceding 12 months was positively and significantly correlated with reported number of recurrences. Results are discussed in terms of their clinical implications. 相似文献
39.
Typical delay determines waiting time on periodic-food schedules: Static and dynamic tests 总被引:6,自引:6,他引:0
下载免费PDF全文

Pigeons and other animals soon learn to wait (pause) after food delivery on periodic-food schedules before resuming the food-rewarded response. Under most conditions the steady-state duration of the average waiting time, t, is a linear function of the typical interfood interval. We describe three experiments designed to explore the limits of this process. In all experiments, t was associated with one key color and the subsequent food delay, T, with another. In the first experiment, we compared the relation between t (waiting time) and T (food delay) under two conditions: when T was held constant, and when T was an inverse function of t. The pigeons could maximize the rate of food delivery under the first condition by setting t to a consistently short value; optimal behavior under the second condition required a linear relation with unit slope between t and T. Despite this difference in optimal policy, the pigeons in both cases showed the same linear relation, with slope less than one, between t and T. This result was confirmed in a second parametric experiment that added a third condition, in which T + t was held constant. Linear waiting appears to be an obligatory rule for pigeons. In a third experiment we arranged for a multiplicative relation between t and T (positive feedback), and produced either very short or very long waiting times as predicted by a quasi-dynamic model in which waiting time is strongly determined by the just-preceding food delay. 相似文献
40.
Rats were allowed to forage in a simulated natural environment made up of eight food sources (patches) each containing a fixed number of pellets. Two of the eight contained an extra supply of peanuts. The peanut patches were signaled by an olfactory/visual cue located at the bottom of the ladder leading to the patch. In successive phases the number of sessions per day, height of the patches, and availability of peanuts were manipulated. Subjects showed evidence of discrimination learning under these conditions, although the degree of discriminatory behavior varied as a function of environmental manipulations. Assessment of behavior within foraging sessions showed that subjects systematically changed their patterns of utilization of patches across time. Sampling or exploration, as well as food reinforcement, seem implicated in these results. 相似文献