全文获取类型
收费全文 | 72023篇 |
免费 | 3444篇 |
国内免费 | 62篇 |
专业分类
75529篇 |
出版年
2020年 | 746篇 |
2019年 | 1012篇 |
2018年 | 1329篇 |
2017年 | 1384篇 |
2016年 | 1413篇 |
2015年 | 1004篇 |
2014年 | 1230篇 |
2013年 | 5824篇 |
2012年 | 2216篇 |
2011年 | 2351篇 |
2010年 | 1598篇 |
2009年 | 1645篇 |
2008年 | 2182篇 |
2007年 | 2121篇 |
2006年 | 1942篇 |
2005年 | 1733篇 |
2004年 | 1696篇 |
2003年 | 1614篇 |
2002年 | 1575篇 |
2001年 | 2253篇 |
2000年 | 2073篇 |
1999年 | 1641篇 |
1998年 | 916篇 |
1997年 | 753篇 |
1996年 | 737篇 |
1995年 | 722篇 |
1994年 | 722篇 |
1992年 | 1341篇 |
1991年 | 1285篇 |
1990年 | 1234篇 |
1989年 | 1182篇 |
1988年 | 1172篇 |
1987年 | 1110篇 |
1986年 | 1098篇 |
1985年 | 1187篇 |
1984年 | 989篇 |
1983年 | 840篇 |
1982年 | 735篇 |
1979年 | 1025篇 |
1978年 | 798篇 |
1976年 | 713篇 |
1975年 | 864篇 |
1974年 | 938篇 |
1973年 | 999篇 |
1972年 | 805篇 |
1971年 | 725篇 |
1969年 | 719篇 |
1968年 | 873篇 |
1967年 | 753篇 |
1966年 | 792篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
931.
932.
Recipient's mood, relationship type, and helping 总被引:6,自引:0,他引:6
M S Clark R Ouellette M C Powell S Milberg 《Journal of personality and social psychology》1987,53(1):94-103
We conducted two studies to examine how a potential helper is affected by having a communal orientation toward a relationship with a potential recipient and by the potential recipient's sadness. We hypothesized that (a) having a communal orientation would increase helping and that (b) people high in communal orientation, but not others, would respond to a potential recipient's sadness by increasing helping. These hypotheses were tested in two studies. In Study 1, individual differences in communal orientation toward relationships were measured by using a new communal orientation scale reported for the first time in this article. In Study 2, manipulations were used to lead subjects to desire either a communal or an exchange relationship with another person. In both studies, subjects were exposed to a sad person or to a person in a neutral mood whom they were given a chance to help. As hypothesized, in both studies communally oriented subjects helped the other significantly more than did others. Also as hypothesized, in both studies communally oriented subjects but not others, increased helping in response to the other person's sadness although this effect reached statistical significance only in the second study. 相似文献
933.
W S Edell 《Journal of personality assessment》1987,51(1):23-41
Qualitative studies have noted that individuals with "borderline" psychopathology exhibit extreme thought disorder on unstructured tests, yet manifest relatively normal performance on more structured tests of cognitive performance. The present study provides empirical support for this clinical observation. Borderline syndrome patients, defined by DSM-III criteria for borderline personality disorder and/or schizotypal personality disorder, demonstrated significantly greater thought disorder on the Rorschach, as measured by Johnston and Holzman's (1979) Thought Disorder Index (TDI), than did nonpsychiatric controls and were indistinguishable from patients with schizophrenic disorder of relatively recent onset. Borderline patients did not differ from controls on a structured test of cognitive slippage. Further examination of the role of structure in the assessment and treatment of borderline syndrome disorders seems warranted. 相似文献
934.
The Threat Index and the Death Anxiety Scale were administered to 228 subjects. Based on the high/low criterion scores, 105 subjects were assigned to the following four groups: (a) high death threat/high death anxiety, (b) high death threat/low death anxiety, (c) low death threat/high death anxiety, and (d) low death threat/low death anxiety. During the experimental phase of the study, subjects viewed a filmstrip on death rituals in various cultures. A recall test was then administered. Results indicated no significant group differences on recall performance. Initial no-show rates for the second part of the experiment were observed in the four groups reflecting a significant negative relationship between death anxiety and initial no-show rates. The possibility of defensive responding on the Death Anxiety Scale was suggested. 相似文献
935.
To determine whether actual responses of potential comforters in the community differ according to cause of death, 83 college students participated in a structured, individual interview. They were asked demographic questions about themselves, the bereaved, and the deceased, and then about various aspects of how they, and others in the community, responded to the death. Students were grouped by their reports of the cause of death (suicide, homicide, accident, natural anticipated death, or natural unanticipated death). When the death was by suicide or homicide, others were perceived as relatively less supportive of the bereaved person. When the death was by suicide, respondents themselves tended more to blame the bereaved person. When the death was by homicide, the bereaved person was perceived as reacting relatively worse. Potential comforters were relatively more shocked when the death was by homicide or accident. 相似文献
936.
937.
Concurrent access to two concentrations of orally delivered phencyclidine: effects of feeding conditions. 总被引:1,自引:1,他引:0
M E Carroll 《Journal of the experimental analysis of behavior》1987,47(3):347-362
Two experiments addressed the effects of food satiation and deprivation on oral self-administration of two concurrently available phencyclidine concentrations. In the first experiment, 8 rhesus monkeys self-administered either of two concentrations of phencyclidine ("PCP, angel dust") and water under concurrent fixed-ratio 16 schedules. One concentration was always held constant (0.25 mg/mL) while a series of other phencyclidine concentrations, ranging from 0 (water) to 1.0 mg/mL, was presented in a nonsystematic order. Initially the monkeys were tested while food satiated, and the procedure was then repeated during food deprivation. The monkeys usually selected the higher concentration within the first few minutes of the session, indicating that taste and/or other immediate postingestional effects were important factors. Contrary to a number of previous reports, there were no consistent differences across subjects in the mean number of liquid deliveries or mean drug intake (mg/kg) during food satiation and deprivation. However, for all monkeys the within-session time course of responding during food satiation consistently differed from that during deprivation. A second experiment assessed whether the failure to find consistent differences in drug intake during food satiation and deprivation had been due to the history of concurrent access to different phencyclidine concentrations or to the extended experience with phencyclidine under food-satiation conditions. Six additional monkeys (Group 2) were exposed to the phencyclidine self-administration procedure (during food satiation and deprivation) for the same length of time as the monkeys in Experiment 1 (Group 1), except they received only concurrent access to phencyclidine (0.25 mg/mL) and water. Both groups then received concurrent access to phencyclidine and water during five repeated cycles of food deprivation and satiation. There were also marked individual differences in Group 2: During food satiation, 2 of the monkeys' responding increased, 1 showed no change, and 3 decreased. Examination of a number of historical variables indicated that the greater the percentage of total sessions spent during food satiation with phencyclidine available (before these experiments began), the greater the amounts of phencyclidine consumed during food satiation and the smaller the differences in phencyclidine intake when the two feeding conditions were compared. 相似文献
938.
The interaction of stimulus and reinforcer control in complex temporal discrimination. 总被引:2,自引:2,他引:0
Six pigeons were trained in a discrete-trials signal-detection procedure to discriminate between a fixed-duration stimulus (5 s or 20 s) and a set of variable durations ranging from 2.5 s to 57.5 s in steps of 5 s. For each fixed-duration stimulus, the ratio of reinforcer frequencies contingent upon reporting the fixed versus the variable stimulus was systematically manipulated. Detection performance was well controlled by both the stimulus value and the reinforcer ratio. Both the discriminability between the fixed duration and the set of variable durations, and the discriminability between the fixed duration and each of the variable durations, were independent of the reinforcer-frequency ratio when discriminability was measured as log d. The sensitivity of response bias to reinforcement-ratio changes was independent of the value of the fixed duration, but was not independent of the discriminability of the variable durations from the fixed durations. Under current models, discriminability measures in complex temporal discrimination may be independent of biasing manipulations, but bias measures are not independent of stimulus values. 相似文献
939.
Pigeons' choices between alternatives that provided different percentages of reinforcement in mixed schedules were studied using the concurrent-chains procedure. In Experiment 1, the alternatives were terminal-link schedules that were equal in delay and magnitude of reinforcement, but that provided different percentages of reinforcement, with one schedule providing, reinforcement twice as reliably as the other. All pigeons preferred the more reliable schedule, and their level of preference was not systematically affected by variation in the absolute percentage values, or in the magnitude of reinforcement. In Experiment 2, preference for a schedule providing 100% reinforcement over one providing 33% reinforcement increased systematically with increases in the duration of the terminal links. In contrast, preference decreased systematically with increases in the duration of the initial links. Experiment 3 examined choice with equal percentages of reinforcement but unequal delays to reinforcement. Preference for the shorter delay to reinforcement was not systematically affected by variation in the absolute percentage of reinforcement. The overall pattern of results supported predictions based on an extension of the delay-reduction hypothesis to choice procedures involving mixed schedules of percentage reinforcement. 相似文献
940.
Effects of delayed conditioned reinforcement in chain schedules. 总被引:3,自引:3,他引:0
The contingency between responding and stimulus change on a chain variable-interval 33-s, variable-interval 33-s, variable-interval 33-s schedule was weakened by interposing 3-s delays between either the first and second or the second and third links. No stimulus change signaled the delay interval and responses could occur during it, so the obtained delays were often shorter than the scheduled delay. When the delay occurred after the initial link, initial-link response rates decreased by an average of 77% with no systematic change in response rates in the second or third links. Response rates in the second link decreased an average of 59% when the delay followed that link, again with little effect on response rates in the first or third links. Because the effect of delaying stimulus change was comparable to the effect of delaying primary reinforcement in a simple variable-interval schedule, and the effect of the unsignaled delay was specific to the link in which the delay occurred, the results provide strong evidence for the concept of conditioned reinforcement. 相似文献