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   80113篇
  免费   2501篇
  国内免费   19篇
  82633篇
  2020年   582篇
  2019年   784篇
  2018年   4214篇
  2017年   3576篇
  2016年   3218篇
  2015年   1016篇
  2014年   1048篇
  2013年   4614篇
  2012年   2335篇
  2011年   4185篇
  2010年   3535篇
  2009年   2599篇
  2008年   3332篇
  2007年   3779篇
  2006年   1685篇
  2005年   1655篇
  2004年   1506篇
  2003年   1394篇
  2002年   1439篇
  2001年   2031篇
  2000年   2030篇
  1999年   1506篇
  1998年   730篇
  1997年   656篇
  1996年   648篇
  1995年   564篇
  1992年   1260篇
  1991年   1156篇
  1990年   1149篇
  1989年   1051篇
  1988年   1038篇
  1987年   984篇
  1986年   1055篇
  1985年   1075篇
  1984年   902篇
  1983年   816篇
  1982年   586篇
  1981年   573篇
  1979年   953篇
  1978年   684篇
  1975年   775篇
  1974年   830篇
  1973年   921篇
  1972年   773篇
  1971年   729篇
  1970年   644篇
  1969年   674篇
  1968年   861篇
  1967年   778篇
  1966年   652篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
911.
Predictions of physical symptomatology by daily life events and by major life events were compared, replicating and expanding work reported by DeLongis, Coyne, Dakof, Folkman, & Lazarus (1982). Analyses of daily, prospective data collected on 79 married men for 90 days demonstrated that daily, undesirable events were better predictors of symptom frequencies than either past, major life events or daily, desirable events. These results, similar to those found by DeLongis et al. (1982), were further explored by examining "healthy" subjects versus subjects with prior medical conditions. Undesirable daily events were a much stronger predictor of physical symptoms in the healthy group than in the prior medical conditions group.  相似文献   
912.
Four groups of rats, one of which served as a normal, nonoperated group, were used. The other three groups were operated and fitted with an electrode carrier of eight electrodes of varying lengths arranged in a 7.5 mm X 5 mm rectangle. About 10 or 12 days after surgery, the following groups of animals underwent a 14-day regimen wherein each animal spent 15 min in a deep, metal, electrically insulated cylinder: Group A, normal, nonoperated group, with no intervention; Group B, stimulated each day with 45 trains of rectangular biphasic pulses (3 trains per min) at the rate of 20 pulses per second (pps); Group C, the same but at the rate of 100 pps; Group D, the same but 180 pps. After a 48-hr fast and without benefit of shaping, each animal was placed for 60 min in a lever-pressing device and was rewarded with a pellet after each three to four presses. The resulting performance curves showed no improvement in pressing rate for Group A; marginal improvement for Group B; definite improvement for Group C; and the greatest improvement for Group D, the terminal rate being almost twice that of Group C.  相似文献   
913.
Children aged 1.5 to 8 years were required to touch accurately an illuminated target lamp located on a vertical board. Movements were made when visual information was complete (target lit for 3 s, room illuminated; partial (target lit for 3 s, room dark, and reduced (target lit for 0.7 s, room dark). Dependent variables were response accuracy, reaction time, and movement time. Accuracy decreased with decreasing availability of visual information and improved with age under all conditions. Reaction times were shorter in the dark (Conditions 2 and 3) than in the light; they decreased with age up to age 5 and did not continue to decrease thereafter. Movement time did not change with age under Conditions 1 and 3 but tended to increase with age under Condition 2. Slower movements were more accurate at all ages, provided visual feedback could be utilized. Increased reliance on the strategy "slower movements yield higher accuracy" was held to account for developmental changes under Condition 2, whereas in Conditions 1 and 3 improvement in the efficiency of motor preprogramming was implicated.  相似文献   
914.
In two experiments we assessed the impact of aggression on nonrapists' sexual arousal. In the first, both male subjects (n = 37) and female subjects (n = 43) reported more sexual arousal in response to nonaggressive than to aggressive depictions when the portrayals were sexually explicit, but the opposite occurred when the portrayals were nonsexual. Only male subjects (N = 359) participated in the second experiment. On the basis of their self-reported sexual arousal to the use of force, they were classified into the no arousal, moderate arousal or high arousal from force groups. To evaluate the veridicality of this classification, we assessed some subjects' (n = 118) penile tumescence in response to various depictions. The findings generally replicated those of the first experiment and confirmed the accuracy of the arousal-from-force classification. The no arousal and the moderate arousal from force subjects were less sexually aroused by aggressive than by nonaggressive portrayals, but the opposite was found for the high arousal from force group. Using the entire sample (N = 359), we also assessed differences on various factors among these three groups. We found strong differences on ideological factors, including acceptance of violence against and dominance over women. We also found differences in acceptance of nonsexual aggression and in subjects' beliefs that they might actually use force against women. In contrast, differences were not found on sexuality factors. The data's implications for theories on the causes of rape are discussed.  相似文献   
915.
We investigated the control judgments of Type A and B actors and observers after five tasks in which actual response-outcome contingency and success were varied systematically. Results indicated that, overall, actors provided higher control judgments than did observers, and both actual contingency and success influenced judged control. Type A and B actors did not differ in their self-perceptions of control but observers judged the Type A actors to have exerted more control than the Type B actors, primarily on positive contingency tasks. These findings suggest that Type As, because of their more active, dynamic style, may be credited by observers with more control or competence than is warranted. By contrast, the more relaxed style of the Type B may lead to lower than warranted evaluations of control or competence. Lastly, Type As were found to learn the contingencies better than Type Bs with important implications for the actual exercise of control.  相似文献   
916.
It was hypothesized that the extent to which individuals' attitudes guide their subsequent perceptions of and behavior toward the attitude object is a function of the accessibility of those attitudes from memory. A field investigation concerning the 1984 presidential election was conducted as a test of these hypotheses. Attitudes toward each of the two candidates, Reagan and Mondale, and the accessibility of those attitudes, as indicated by the latency of response to the attitudinal inquiry, were measured for a large sample of townspeople months before the election. Judgments of the performance of the candidates during the televised debates served as the measure of subsequent perceptions, and voting served as the measure of subsequent behavior. As predicted, both the attitude-perception and the attitude-behavior relations were moderated by attitude accessibility. The implications of these findings for theoretical models of the processes by which attitudes guide behavior, along with their practical implications for survey research, are discussed.  相似文献   
917.
Altruism and aggression: the heritability of individual differences   总被引:8,自引:0,他引:8  
Five questionnaires measuring altruistic and aggressive tendencies were completed by 573 adult twin pairs of both sexes from the University of London Institute of Psychiatry Volunteer Twin Register. The questionnaires measured altruism, empathy, nurturance, aggressiveness, and assertiveness. The intraclass correlations for the five scales, respectively, were .53, .54, .49, .40, and .52 for 296 monozygotic pairs, and .25, .20, .14, .04, and .20 for 179 same-sex dizygotic pairs, resulting in broad heritability estimates of 56%, 68%, 70%, 72%, and 64%. Additional analyses, using maximum-likelihood model-fitting, revealed approximately 50% of the variance on each scale to be associated with genetic effects, virtually 0% with the twins' common environment, and the remaining 50% with each twins' specific environment and/or error associated with the test. Correcting for the unreliability in the tests raised the maximum-likelihood heritabilities to approximately 60%. Age and sex differences were also found: altruism increased over the age span from 19 to 60, whereas aggressiveness decreased, and, at each age, women had higher scores than men on altruism and lower scores on aggressiveness.  相似文献   
918.
Generalization of four retarded children's object naming responses to stimuli in the natural environment was assessed after training with either objects or pictures of the objects. Generalization was typically greater after training with objects. In a second experiment, half of the stimuli that showed little generalization were retrained by alternating the original training object with an object that belonged to the same stimulus class as the training stimulus. The other half were simply retrained using the object. The alternating procedure resulted in substantial increases in generalization to untrained objects.  相似文献   
919.
We examined the effects of behavioral procedures to modify the food choices of preschoolers during a snack period at school (training setting) and at home (generalization setting). In the first experiment, we evaluated the usefulness of nutrition training and a generalization programming strategy of cueing to improve healthy snacking; in the second experiment we investigated the effect of nutrition training alone. In addition, three cases are presented that illustrate individualized procedures to facilitate generalization of healthy snacking to home. Results indicated that children's healthy snack choices increased in the preschool training setting, that generalization to home was achieved only when procedures to program it were implemented, and that the best results were found when the generalization procedures were tailored to the individual child.  相似文献   
920.
Questionnaires concerning attitudes toward use of microcomputers at home, in school, and at video arcades were administered to 879 high school students. Direct observations of adolescent proxemics and sex differences, and of various parameters of video games in 18 video arcades were made. A thorough and representative content analysis of sex bias of microcomputer software advertising brochures was carried out. Results supported previous findings of overrepresentation of masculine culture in the adolescent world of microcomputers, particularly regarding video games. Various types of computer-related activity were not related to socioeconomic class of the parents or to academic grades except for use of home microcomputers, which was mildly positively related to socioeconomic class (r = .124, p less than .001). Nearly half the activity in the arcades was strictly solitary. None of the arcade video games allowed for cooperative play. Most allowed only for sequential competition (86%) or simultaneous competition (7%); as many as 7% did not provide a display of the scores for a second player.  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