全文获取类型
收费全文 | 1875篇 |
免费 | 963篇 |
国内免费 | 32篇 |
专业分类
2870篇 |
出版年
2013年 | 98篇 |
2012年 | 17篇 |
2011年 | 39篇 |
2010年 | 91篇 |
2009年 | 166篇 |
2008年 | 63篇 |
2007年 | 77篇 |
2006年 | 38篇 |
2005年 | 52篇 |
2004年 | 75篇 |
2003年 | 73篇 |
2002年 | 43篇 |
2001年 | 117篇 |
2000年 | 42篇 |
1999年 | 77篇 |
1998年 | 73篇 |
1997年 | 48篇 |
1996年 | 88篇 |
1995年 | 68篇 |
1994年 | 72篇 |
1993年 | 67篇 |
1992年 | 84篇 |
1991年 | 86篇 |
1990年 | 74篇 |
1989年 | 79篇 |
1988年 | 60篇 |
1987年 | 49篇 |
1986年 | 40篇 |
1985年 | 33篇 |
1984年 | 31篇 |
1982年 | 41篇 |
1981年 | 26篇 |
1980年 | 24篇 |
1979年 | 26篇 |
1976年 | 21篇 |
1974年 | 18篇 |
1973年 | 31篇 |
1972年 | 45篇 |
1971年 | 42篇 |
1970年 | 28篇 |
1969年 | 30篇 |
1968年 | 56篇 |
1967年 | 38篇 |
1966年 | 49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2870条查询结果,搜索用时 15 毫秒
131.
Changes in respiration associated with schedule-controlled behavior were determined in seated rhesus monkeys prepared with a pressure-displacement head plethysmograph for monitoring ventilation continuously during behavioral experiments. Subjects were trained to press a lever under fixed-ratio 40 and fixed-interval 300-s schedules of stimulus termination. Episodic increases in ventilation were closely associated with periods of responding under both schedules. Recurring episodes of increased ventilation occurred during fixed-ratio responding, and were separated by brief 10-s timeouts during which ventilation decreased. Under the fixed-interval schedule, both ventilation and response rate typically increased as the 300-s interval elapsed. The effects of cocaine, caffeine, and two adenosine agonists, 5'-N-ethylcarboxamidadenosine (NECA) and 2-(carboxyethylphenylamino)adenosine-5'-carboxamide (CGS 21680), on behavior and respiration were determined using a cumulative-dosing procedure. Drug-induced suppression of behavior eliminated the episodic increases in ventilation during the performance components of both schedules. Schedule-related increases in ventilation were compared to those produced by elevated levels of CO2 in inspired air. Exposure to 4% CO2 mixed in air increased ventilation in all subjects, and the combined effects of CO2 exposure and schedule-controlled responding on respiration appeared to be additive. The results suggest that behavioral activities may increase ventilation through increased metabolic demand and increased CO2 production. 相似文献
132.
M J Evans A Duvel M L Funk B Lehman J Sparrow N T Watson A Neuringer 《Journal of the experimental analysis of behavior》1994,62(1):149-156
An apparatus was developed to study social reinforcement in the rat. Four Long-Evans female rats were trained to press a lever via shaping, with the reinforcer being access to a castrated male rat. Responding under a fixed-ratio schedule and in extinction was also observed. Social access was found to be an effective reinforcer. When social reinforcement was compared with food reinforcement under similar conditions of deprivation and reinforcer duration, no significant differences were observed. 相似文献
133.
Choice responding by adult humans in a discrete-trial task was examined as a function of conditions that manipulated either the delay to point delivery or the delay between points and their exchange for money. In point-delay conditions, subjects chose between an "impulsive" alternative that provided a small amount of points immediately and a "self-control" alternative that provided a larger amount of points delayed by 15, 30, or 60 s. Points were exchanged for money immediately following the session. Subjects preferred the self-control alternative. In exchange-delay conditions, subjects chose between a small amount of points exchangeable for money immediately following the session and a larger amount of points exchangeable for money after 1 day, 3 weeks, or 6 weeks. A self-control preference observed for all subjects in the 1-day exchange-delay condition reversed to exclusive impulsive preference for 4 of the 6 subjects when choice conditions involved exchange delays of 3 or 6 weeks. These results show that human choice is sensitive to the manipulation of exchange delays and that impulsive preference can be obtained with exchange delays on the order of weeks. 相似文献
134.
Three rats, lever pressing for food delivered on a fixed-interval 128-s schedule, were presented with a 16-s opportunity to drink from a retractable water source. The temporal placement of the water probe within the reinforcement cycle was varied sequentially, in steps of 16 s. Although the lever-pressing pattern was modulated by the intercalated water probe, water consumption during the probe itself was a decreasing function of time from the following reinforcer. These results were interpreted as evidence against the notion that schedule-induced drinking is a "ubiquitous" phenomenon and are congruent with results from other "intruded stimulus" experiments. 相似文献
135.
Seven undergraduates participated in a concurrent-choice experiment with monetary reinforcers. Response-independent analogues of variable-interval and variable-ratio schedules were used to assess whether subjects would maximize reinforcement rate. The optimal pattern of behavior, in terms of maximizing reinforcement rate, involved a large bias toward the ratio alternative, with only occasional sampling of the interval schedule. Most experiments with pigeons, however, demonstrate matching of response rates to reinforcement rates, with only slight biases for the ratio schedule. Although subjects in the present experiment allocated more time to the ratio alternative than required by matching, the magnitude of the bias did not approximate that predicted by a maximizing account. After exposure to clock stimuli correlated with the operation of each schedule, 1 subject's behavior did show a substantial level of bias, increasing the total number of reinforcers obtained, and lay at a point between the predictions of matching and maximizing. The other subjects, however, continued to respond less optimally. The present results can be accounted for by a view of matching that incorporates the effects of delayed reinforcement. 相似文献
136.
Four empirical studies of the roles of self-report questionnaires, tests, and ratings in employment interviews, staff appraisal,
and personnel validation surveys are presented in order to examine the number and relationships of psychological constructs
derived from data provided by candidates, employees, and their assessors. Test results are related to different kinds of criteria,
including job offers following interview, supervisor ratings on the job, and objective indices of work performance. From the
practices reported and observed in these various contexts, a theory of personal appraisal mechanisms in occupational settings
is derived using data reduction and linear regression methods. Applications of cognitive information processing theory to
self-reports and ratings by individuals, and of exchange theory to the social context of panel discussions among assessors,
provide a key to understanding why psychometric measures of personal qualities vary in their power to predict work performance
in spite of consistent construct validity. 相似文献
137.
Previous research indicates that vasopressin-containing (LE) rats are capable of adapting to the stress of food restriction,
whereas vasopressin-deficient (DI) rats cannot adapt to this stressor. It has been postulated that abnormalities in glucose
metabolism may be one of the factors leading to the demise of food-restricted DI rats. The present study was conducted to
determine if taste preferences are altered in DI animals and if the presentation of exogenous glucose, in the form of sucrose
solutions, can ameliorate the effects of the stress of food restriction. Four different concentrations of sucrose solutions
were presented to LE and DI rats under the food-restricted condition. In both strains, an 8% sucrose solution was preferred
over 0%, 16%, and 32% concentrations, with DI rats consuming more of this concentration than LE rats. Thus, when DI rats had
the opportunity of maintaining glucose homeostasis by exogenous supplements, they maintained body weight, displayed no stomach
pathology, and survived. 相似文献
138.
In contrast to previous research on apologies, which has examined their role in enhancing impressions of those issuing them
(e.g., Darby and Schlenker, 1989), the research reported here draws upon Goffman’s (1955) analysis of the “corrective cycle”
and is concerned with constraints associated with the receipt of apologies. Study 1 examines the implications for the actor
of accepting, not accepting, or rejecting apologies. It is demonstrated that across a variety of judgments, most positive
views of the actor result when apologies are accepted; least positive views are associated with their rejection. A follow-up
study sought to establish whether this effect would occur under circumstances in which unconvincing apologies are rejected.
Results indicate that the apology’s status (convincing versus unconvincing) has no bearing on perceptions of actors. Based
on a hypothetical role-play format, Study 2 addresses the matter of whether actors experience a subjective sense of constraint
upon receipt of unsatisfactory apologies. The data suggest that there exists a pronounced tendency to accept such apologies,
though typically with conditions that would be specified to the offender. More general implications of the data are discussed. 相似文献
139.
This study presents two experiments that demonstrate that the memory trace of a tobe-remembered item develops along a dimension
(continuum) from coarse/general to fine/specific. Similarly, forgetting is shown to be a reverse movement along this dimension
from fine to coarse, as increasingly less fine attributes are lost. The attribute acquisition pattern of this Progressively
Finer Attributes Theory is robust and predictable, valid for experimentally unstructured (Experiment 2) as well as experimentally
structured (Experiment 1) material. 相似文献
140.
Conflicting findings have been reported concerning whether fluent children use more complex syntactic structures than stutterers and whether or not stutterers experience specific difficulty with complex syntactic structures. On critical examination, the first of these apparent discrepancies appears to be due to (a) differences in the methods employed for syntactic analysis in different studies, and (b) misleading impressions gained by looking at speakers within a single age range. Data were reanalyzed where one method of analysis had shown that fluent speakers and stutterers did not differ with regard to syntactic structures used but where they did show a propensity for stuttering to occur on complex syntactic structures. These data cover a range of age groups. When the second method of syntactic analysis was applied, a difference was found between fluent speakers and stutterers, with the stutterers initially using more simple structures and fewer complex ones. This difference decreased over age groups. However, a difference still remained with respect to which syntactic structures stutterers experience difficulty. An additional analysis, not formerly conducted on these data, showed that, as reported elsewhere, there was a higher probability of stuttering on clause-initial and. It was also shown that this tendency decreased with age group of the stutterers. 相似文献