全文获取类型
收费全文 | 1969篇 |
免费 | 977篇 |
国内免费 | 32篇 |
专业分类
2978篇 |
出版年
2013年 | 116篇 |
2012年 | 27篇 |
2011年 | 48篇 |
2010年 | 93篇 |
2009年 | 171篇 |
2008年 | 69篇 |
2007年 | 83篇 |
2006年 | 40篇 |
2005年 | 58篇 |
2004年 | 79篇 |
2003年 | 77篇 |
2002年 | 45篇 |
2001年 | 117篇 |
2000年 | 45篇 |
1999年 | 77篇 |
1998年 | 74篇 |
1997年 | 48篇 |
1996年 | 87篇 |
1995年 | 67篇 |
1994年 | 72篇 |
1993年 | 67篇 |
1992年 | 85篇 |
1991年 | 87篇 |
1990年 | 74篇 |
1989年 | 76篇 |
1988年 | 59篇 |
1987年 | 46篇 |
1986年 | 41篇 |
1985年 | 32篇 |
1984年 | 31篇 |
1982年 | 39篇 |
1981年 | 25篇 |
1980年 | 24篇 |
1979年 | 24篇 |
1976年 | 20篇 |
1974年 | 17篇 |
1973年 | 31篇 |
1972年 | 44篇 |
1971年 | 42篇 |
1970年 | 27篇 |
1969年 | 29篇 |
1968年 | 56篇 |
1967年 | 38篇 |
1966年 | 48篇 |
1965年 | 40篇 |
1964年 | 80篇 |
1963年 | 73篇 |
1962年 | 48篇 |
1961年 | 38篇 |
1959年 | 16篇 |
排序方式: 共有2978条查询结果,搜索用时 7 毫秒
31.
The proposal that peripheral visual changes (cues) tend to summon attention automatically was tested by studying the effect
of peripheral cueing on simple detection latency. Delay between cue onset and target onset, the contingent relationship between
cue location and target location, and instructions to subjects were manipulated. Results showed that a peripheral display
change could capture attention even when the target was far more likely to appear at an uncued location. When subjects were
explicitly informed that targets were likely to appear away from the cued location they were able to suppress this effect,
but were unable completely to reverse it by rapidly orienting attention towards the uncued side. Hence the process appears
to be automatic in the sense that it occurs unless there are explicit instructions to the contrary. With explicit instructions
the processing operation can be suppressed, but not completely reversed.
This work was supported by the U.K. Admiralty Research Establishment (Research Agreement No. 53482). 相似文献
32.
Clinical staff’s attributions about diabetes management were measured using newly developed scales. Eighty-five physicians
and nurses provided data to investigate the psychometric properties of the scales and to examine the patterns of attributions
made. Alpha coefficients for the 7 six-item scales were satisfactory, ranging from .51 to .73. A comparison between attributions
for positive and negative outcomes of diabetes management produced examples of self-serving bias. Comparisons were made with
data from 286 insulin-dependent diabetes patients. Staff tended to rate patients as having less personal control over positive
outcomes (t=2.94;df=338;p<.01) and tended to emphasize chance to a greater extent than did the patients (t=−4.32;df=338;p<.001). There was a tendency for staff to rate negative outcomes as being more foreseeable by the patients than the patients
did themselves (t=−3.11;df=346;p<.01). Both patients and staff demonstrated bias towards dispositional attributions. The implications of between and within
group differences in attribution patterns are discussed.
The research presented here was supported in part by grants from the National Institutes of Health, U.S.A. (No. AM28196) and
from the British Diabetic Association to Dr. C. Bradley. 相似文献
33.
This study set out to investigate the relationship between the Type A behavior pattern, the need for approval, and the need
to prove oneself. One hundred and two subjects completed four questionnaires: two measuring A-type behavior, one social desirability,
and one—especially devised for this study—the belief in the need to prove oneself consistently. Results showed that Type A’s
have significantly lower needs for approval than Type B’s, yet appear to show considerably greater interest in comparing their
achievements with others. It seems that Type A’s do not have any special need to prove their worth to others, but that they
must constantly prove themselves to themselves. Limitations of this preliminary study are discussed. 相似文献
34.
Sixteen student volunteers were administered a placebo and 50 mg. of chlorpromazine in tablet form, on separate occasions,
two hours before testing. The three tests measured dichotic listening performance, lateral eye movements while answering questions
about spatial location and verbal meaning, and lateralized facial expression while relating pleasant and unpleasant life incidents.
Results showed that chlorpromazine increased the number of trials showing an ear advantage in dichotic listening. Chlorpromazine
reduced lateral and increased vertical eye movements in response to the questions about spatial location and verbal meaning.
Under the placebo both negative and positive emotions were expressed more in the left face. Although chlorpromazine did not
affect this lateralization of negative emotions, the expression of positive emotions occurred equally often on the two sides
of the face under chlorpromazine. Results may be related to an effect of chlorpromazine on the asymmetrical dopamine pathways
of the brain. It is suggested that the findings may be related to a left hemisphere deficit in schizophrenia. 相似文献
35.
Observational learning of two visual discriminations by pigeons: a within-subjects design. 下载免费PDF全文
G B Biederman H A Robertson M Vanayan 《Journal of the experimental analysis of behavior》1986,46(1):45-49
Pigeon's observational learning of successive visual discrimination was studied using within-subject comparisons of data from three experimental conditions. Two pairs of discriminative stimuli were used; each bird was exposed to two of the three experimental conditions, with different pairs of stimuli used in a given bird's two conditions. In one condition, observers were exposed to visual discriminative stimuli only. In a second condition, subjects were exposed to a randomly alternating sequence of two stimuli where the one that would subsequently be used as S+ was paired with the operation of the grain magazine. In a third experimental condition, subjects were exposed to the performance of a conspecific in the operant discrimination procedure. After exposures to conspecific performances, there was facilitation of discriminative learning, relative to that which followed exposures to stimulus and reinforcement sequences or exposures to stimulus sequences alone. Exposure to stimulus and food-delivery sequences enhanced performance relative to exposure to stimulus sequences alone. The differential effects of these three types of exposure were not attributable to order effects or to task difficulty; rather, they clearly were due to the type of exposure. 相似文献
36.
DOES EFFORT PLAY A ROLE IN THE EFFECT OF RESPONSE REQUIREMENTS ON DELAYED MATCHING TO SAMPLE? 总被引:2,自引:2,他引:0 下载免费PDF全文
The possible role of "effort" in the accuracy of pigeons' performance on a delayed matching-to-sample procedure was investigated by examining the effects of response requirements that accompanied a trial-initiating stimulus and that accompanied a sample stimulus. In the first experiment, the effect of varying the size of a fixed-ratio requirement for responses during an initiating stimulus was compared to that of varying a similar requirement for responses during the sample stimulus. Accuracy increased reliably with increases in the ratio scheduled during the sample stimulus, but was not significantly affected by increases in the ratio scheduled on the key during the initiating stimulus. In another phase of Experiment 1, sample duration was held constant while the ratio requirement was varied during the initiating stimulus. Again, accuracy of matching to sample was not significantly affected by the size of the ratio scheduled during the initiating stimulus. Experiment 2 provided a systematic replication of these results in another group of pigeons and included a more detailed analysis of responding. These results support the view that increases in sample-response requirement facilitate accuracy of delayed matching by increasing the durations of exposure to the sample stimuli, and do not support a role of effort in the sample-response effect. In Experiment 3, the facilitative effect of responses on the sample but not of those on the initiating stimulus was replicated using a simultaneous matching-to-sample procedure. This finding provides further evidence against an interpretation of response-requirement effects that appeals to effort; the finding also suggests that sample exposure might affect initial discrimination of the sample rather than remembering the sample. 相似文献
37.
R Pisacreta D Gough E Redwood L Goodfellow 《Journal of the experimental analysis of behavior》1986,45(3):269-282
Four pigeons were trained on a multiple variable-interval 30-s extinction schedule with various pairs of spoken English words presented as the discriminative stimuli. The birds typically produced discrimination indices of 70% to 90% accuracy. Discrimination accuracy was improved by shortening the interval between auditory stimulus presentations, and by increasing the number of syllables in the words. 相似文献
38.
It has been suggested that the failure to maximize reinforcement on concurrent variable-interval, variable-ratio schedules may be misleading. Inasmuch as response costs are not directly measured, it is possible that subjects are optimally balancing the benefits of reinforcement against the costs of responding. To evaluate this hypothesis, pigeons were tested in a procedure in which interval and ratio schedules had equal response costs. On a concurrent variable time (VT), variable ratio-time (VRT) schedule, the VT schedule runs throughout the session and the VRT schedule is controlled by responses to a changeover key that switches from one schedule to the other. Reinforcement is presented independent of response. This schedule retains the essential features of concurrent VI VR, but eliminates differential response costs for the two alternatives. It therefore also eliminates at least one significant ambiguity about the reinforcement maximizing performance. Pigeons did not maximize rate of reinforcement on this procedure. Instead, their times spent on the alternative schedules matched the relative rates of reinforcement, even when schedule parameters were such that matching earned the lowest possible overall rate of reinforcement. It was further shown that the observed matching was not a procedural artifact arising from the constraints built into the schedule. 相似文献
39.
Drug-behavior interaction history: modification of the effects of morphine on punished behavior. 总被引:1,自引:1,他引:0 下载免费PDF全文
Squirrel monkeys were trained to respond under a multiple fixed-interval, fixed-interval schedule in which the first response after 5 min terminated a visual stimulus in the presence of which electric shocks could occur. During one component of the schedule, correlated with one color of stimulus lights, every 30th response also produced electric shock; responding was suppressed during this component to approximately 10 to 12% of that occurring in the alternate component in which responding was not punished. In contrast to previous research, morphine (0.03 to 1.0 mg/kg) increased punished responding. Unpunished responding, however, was either not affected or decreased at doses of morphine that increased punished responding. Increases in rate of punished responding also occurred when the single-schedule punishment condition was studied alone in these animals. Subsequent experimentation, which systematically analyzed the development of the rate-enhancing effects of morphine on punished responding, involved the study of drug effects in additional monkeys trained initially under a single-schedule punishment condition. The effects of morphine on punished responding were studied before, after, and then during exposure to the multiple schedule that included a component in which responding was not punished. Increases in response rate with morphine did not occur until it was administered during exposure to the multiple schedule that included a component in which responding was not punished. As with the other monkeys, once the rate increases in punished responding occurred under the multiple schedule, these effects of morphine persisted, even when the multiple schedule was removed.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
40.
Cognitive, motivational, social, and environmental influences on children's food choices 总被引:2,自引:0,他引:2
This study tested the applicability of a cognitive-motivational model of health behavior to children's food choices. A sample of 107 elementary schoolchildren provided ratings of 15 foods in terms of possible choice criteria (e.g., how tasty or healthful specific foods were) and social or environmental influences (e.g., whether foods were eaten by friends or were easy to get). Several measures of food consumption were taken, and cognitive-developmental level was assessed. Within-person correlations were calculated between food choices and each choice criterion and social/environmental factor. These "correlational indices" of influences on food choice subsequently were used to identify five distinct subgroups in the sample. Children at the operational level of cognitive development tended to be in one of three groups characterized by health orientation in food choice, taste orientation, or multiple-motive orientation. Dietary quality was poorest in the taste-oriented group. Children at the preoperational level tended to have one of two undifferentiated patterns of values across the correlational indices. Results provide evidence of: the viability of cognitive-motivational models to explain children's food choices, the promise of within-person research methodology, and the potential for enhanced health behavior-change programs by use of population segmentation and tailored interventions. 相似文献