首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   11215篇
  免费   298篇
  国内免费   54篇
  2018年   17篇
  2012年   1232篇
  2011年   1301篇
  2010年   321篇
  2009年   131篇
  2008年   1048篇
  2007年   1060篇
  2006年   965篇
  2005年   815篇
  2004年   668篇
  2003年   681篇
  2002年   566篇
  2001年   443篇
  2000年   509篇
  1999年   205篇
  1998年   51篇
  1997年   49篇
  1996年   38篇
  1995年   35篇
  1994年   46篇
  1993年   46篇
  1992年   42篇
  1991年   45篇
  1990年   49篇
  1989年   44篇
  1988年   56篇
  1987年   40篇
  1986年   49篇
  1985年   47篇
  1984年   34篇
  1983年   40篇
  1982年   26篇
  1981年   42篇
  1980年   21篇
  1979年   27篇
  1978年   32篇
  1965年   22篇
  1963年   22篇
  1959年   28篇
  1958年   79篇
  1957年   74篇
  1956年   64篇
  1955年   46篇
  1954年   46篇
  1953年   49篇
  1952年   39篇
  1951年   24篇
  1950年   23篇
  1949年   18篇
  1948年   19篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
181.
This work advances an interdependence theoretic analysis of the role of self-respect in ongoing close relationships. Self-respect is defined as the tendency to perceive the self as a principled person who is worthy of honor and high regard and is argued to rest on moral integrity. Consistent with predictions, results from a study of marital relationships revealed that individual self-respect is positively associated with both the individual's and the partner's pro-relationship behavior (accommodation, forgiveness, conciliation). Mediation analyses revealed that self-respect not only exhibits direct associations with each person's behavior, but also exhibits indirect associations with each person's behavior, via the impact of each person's actions on reciprocal pro-relationship behavior from the partner. Mediation was more reliably observed for the association of self-respect with partner behavior than for the association with individual behavior. Both individual pro-relationship behavior and partner pro-relationship behavior are positively associated with couple well-being, which in turn is positively associated with personal well-being (life satisfaction, physical health, psychological adjustment). These associations were evident in both within-participant and across-partner analyses and for both self-report and interaction-based measures of behavior. Self-respect reliably accounts for unique variance beyond variance attributable to self-esteem.  相似文献   
182.
The perception of group variability is affected by social power and status. Three different mechanisms may be responsible for these effects: (a) the power of the perceiver affects perceived group variability; (b) the power of the perceived group affects its perceived variability; and (c) the power of the group affects its actual variability. Two studies are reported to tease apart these three mechanisms and provide support for the third. In the first study, high- and low-power groups interacted and subsequently judged each other. In the second study, participants observed and rated the Study 1 groups, either knowing their power relationship or not. Results suggest that members of high-power groups manifest greater interpersonal variability than members of low-power groups.  相似文献   
183.
From an early age, children can go beyond rote memorization to form links between print and speech that are based on letter names in the initial positions of words (Treiman & Rodriguez, 1999; Treiman, Sotak, & Bowman, 2001). For example, children's knowledge of the name of the letter t helps them learn that the novel word TM is pronounced as team. Four experiments were carried out to determine whether letter names at the ends of words are equally useful. Four- and five-year-olds derived little benefit from such information in reading (Experiments 1 and 3) or spelling (Experiment 2), although adults did (Experiment 4). For young children, word-final information appears to have less influence on reading and spelling performance than does word-initial information. The results help delineate the circumstances under which children can go beyond a logographic approach in learning about print.  相似文献   
184.
Pigeons were trained in a procedure in which sessions included seven four- or 10-reinforcer components, each providing a different reinforcer ratio that ranged from 27:1 to 1:27. The components were arranged in random order, and no signals differentiated the component reinforcer ratios. Each condition lasted 50 sessions, and the data from the last 35 sessions were analyzed. Previous results using 10-s blackouts between components showed some carryover of preference from one component to the next, and this effect was investigated in Experiment 1 by varying blackout duration from 1 s to 120 s. The amount of carryover decreased monotonically as the blackout duration was lengthened. Preference also decreased between reinforcers within components, suggesting that preference change during blackout might follow the same function as preference change between reinforcers. Experiment 2 was designed to measure preference change between components more directly and to relate this to preference change during blackout. In two conditions a 60-s blackout occurred between components, and in two other conditions a 60-s period of unsignaled extinction occurred between components. Preference during the extinction period progressively fell toward indifference, and the level of preference following extinction was much the same as that following blackout. Although these results are consistent with Davison and Baum's (2000) theory of the effects of reinforcers on local preference, other findings suggest that theory is incomplete: After a sequence of reinforcers from one alternative, some residual preference remained after 60 s of extinction or blackout, indicating the possibility of an additional longer term accumulation of reinforcer effects than originally suggested.  相似文献   
185.
Pigeons were trained to discriminate 5 mg/kg pentobarbital from saline under concurrent variable-ratio (VR) VR schedules, in which responses on the pentobarbital-biased lever were reinforced under the VR schedule with the smaller response requirements when pentobarbital was given before the session, and responses on the saline-biased key were reinforced under the VR schedule with the larger response requirements. When saline was administered before the session, the reinforcement contingencies associated with the two response keys were reversed. When responding stabilized under concurrent VR 20 VR 30, concurrent VR 10 VR 40, or concurrent VR 5 VR 50 schedules, pigeons responded almost exclusively on the key on which fewer responses were required to produce the reinforcer. When other doses of pentobarbital and other drugs were substituted for the training dose, low doses of all drugs produced responding on the saline-biased key. Higher doses of pentobarbital and chlordiazepoxide produced responding only on the pentobarbital-biased key, whereas higher doses of ethanol and phencyclidine produced responding only on this key less often. d-Amphetamine produced responding primarily on the saline-biased key. When drugs generalized to pentobarbital, the shape of the generalization curve under concurrent VR VR schedules was more often graded than quantal in shape. Thus, drug discrimination can be established under concurrent VR VR schedules, but the shapes of drug-discrimination dose-response curves under concurrent VR VR schedules more closely resemble those seen under interval schedules than those seen under fixed-ratio schedules. Graded dose-response curves under concurrent VR VR schedules may relate to probability matching and difficulty in discriminating differences in reinforcement frequency.  相似文献   
186.
In 2 studies, the authors investigated intergroup violence as perceived by Israeli Jews and Israeli Arabs. University and junior high school students judged Jewish-Arab clashes, which ended in shots fired at a crowd of either Jewish or Arab demonstrators. The authors hypothesized that judgments of these shootings would be contingent on 3 variables: the origin of the respondent, the origin of the shooter, and the level of danger to the shooter. The results tended to support those hypotheses: (a) Both Jewish and Arab respondents justified shootings by members of their own group more readily than those by members of the other group. (b) Jewish judgments of violence were associated more closely than Arab judgments with the danger that the demonstrators posed to the shooter. (c) The Jewish respondents referred to self-defense more often than did the Arab respondents to justify their judgments, whereas the Arab respondents referred more often to intergroup considerations. Those differences may reflect the disagreement between the majority and the minority on the issue that each group should take into consideration in cases of international violence.  相似文献   
187.
188.
The transformation of functions refers to the untrained acquisition of stimulus functions among members of stimulus equivalence classes or relational frames. Although it is widely assumed that contextual control over the transformation of fuctions must exist, this has not yet been conclusively demonstrated in laboratory studies. Four experiments are reported in which (a) stimulus equivalence classes were established, (b) a conditional stimulus function was trained for one member of each of the classes, and (c) multiple-exemplar procedures were used to train and test for contextual control over the transformation of the stimulus function within the classes and to assess whether it generalized to new equivalence classes. Although a significant amount of training was required, the procedures ultimately resulted in the contextual control of function transformation for 9 of 10 participants and generalized contextual control for 4 of 5 participants.  相似文献   
189.
31 college age men and women who consume less than three caffeinated beverages per week agreed to participate as subjects in research on the effects of acute caffeine intake on low intensity task performance. All subjects performed two randomly administered test conditions: (1) caffeine (5 mg/kg) and (2) placebo on separate visits following an initial 1-hr. orientation visit. Subjects were administered the beverage 30 min. prior to performing 12 separate tests assessing basic mathematics, simple response, logical reasoning, hand-eye coordination, and spatial and assembly skills. The Spielberger State Anxiety test was administered immediately after consuming the test beverage and once again at posttest. Analysis showed that caffeine did not significantly affect performance on all tests with the exception of the peripheral awareness (hand-eye coordination) test on which performance was higher after ingesting caffeine. The placebo treatment produced no effect on state anxiety, which contrasted with a significant rise in anxiety after caffeine consumption. State anxiety values were significantly greater after caffeine treatment relative to the placebo at pretest, and this difference persisted at posttest. These results demonstrated that the dose of caffeine increased scores on state anxiety for individuals who consumed less than three caffeinated beverages weekly but had very little effect on performance of low intensity tasks, except for a hand-eye coordination test involving peripheral awareness. Perhaps longer continuous performance of more demanding tasks would be more sensitive.  相似文献   
190.
Olivopontocerebellar atrophy (OPCA) is a still debated condition, of which motor disruption is the most common feature. A high incidence of associated mood disorders may exist, but there are few studies on concomitant cognitive impairment. Our aim was to assess whether there is reading and writing disruption in olivopontocerebellar atrophy (OPCA). 6 patients were administered different reading and writing tasks. Scores were then compared to those obtained by healthy volunteers. There was an evident impairment in reading and writing execution in our patients compared to those of the control group. On the contrary, no difference could be found in abstraction, problem-solving, and memory tasks. We discuss the results, debating the role of the cerebellum in the conscious process of cognition or in ocular movement control (necessary for reading and writing fluidity and effective execution) and in the dynamic activation of all the cerebral cortex mediated by the diffuse projection to the reticular system.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号