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   25995篇
  免费   1054篇
  国内免费   347篇
  2019年   261篇
  2018年   398篇
  2017年   414篇
  2016年   428篇
  2015年   306篇
  2014年   387篇
  2013年   1866篇
  2012年   665篇
  2011年   733篇
  2010年   529篇
  2009年   490篇
  2008年   729篇
  2007年   693篇
  2006年   674篇
  2005年   557篇
  2004年   529篇
  2003年   513篇
  2002年   510篇
  2001年   656篇
  2000年   663篇
  1999年   522篇
  1998年   277篇
  1997年   286篇
  1996年   279篇
  1995年   265篇
  1992年   494篇
  1991年   452篇
  1990年   445篇
  1989年   425篇
  1988年   441篇
  1987年   409篇
  1986年   451篇
  1985年   428篇
  1984年   379篇
  1983年   333篇
  1981年   267篇
  1979年   403篇
  1978年   322篇
  1977年   280篇
  1976年   292篇
  1975年   337篇
  1974年   428篇
  1973年   462篇
  1972年   341篇
  1971年   365篇
  1970年   334篇
  1969年   361篇
  1968年   434篇
  1967年   399篇
  1966年   416篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
901.
Because the World-Wide Web has features that are not found in traditional information systems, it has some unique problems pertaining to human use, such as the difficulty of searching for specific information. This paper describes human cognitive limitations pertinent to the design of Web browsers and provides a conceptual model for human information processing on the Web. It also compares user strategies and use of browser functions for two tasks that differ in the specificity of the information that is to be retrieved. General principles and specific recommendations for the design of Web browsers are derived from these considerations.  相似文献   
902.
Nonparametric regression techniques, which estimate functions directly from noisy data rather than relying on specific parametric models, now play a central role in statistical analysis. We can improve the efficiency and other aspects of a nonparametric curve estimate by using prior knowledge about general features of the curve in the smoothing process. Spline smoothing is extended in this paper to express this prior knowledge in the form of a linear differential operator that annihilates a specified parametric model for the data. Roughness in the fitted function is defined in terms of the integrated square of this operator applied to the fitted function. A fastO(n) algorithm is outlined for this smart smoothing process. Illustrations are provided of where this technique proves useful.  相似文献   
903.
高杨  匡培梓 《心理科学》1997,20(3):202-205
以2日龄雏鸡为研究对象,采用一次性被动回避学习模型,以不透明胶纸封贴一侧眼的方法,研究2日龄雏鸡单侧眼视剥夺2小时后对视觉学习记忆的影响,并与双眼学习条件下的记忆情况进行比较;试图探讨雏鸡在视觉信息加工过程中左、右半球的作用。实验结果表明:剥夺一侧眼(无论左或右)2小时后对雏鸡的短时记忆无影响,明显干扰雏鸡的中期和长时记忆,特别是剥夺左眼干扰更明显。  相似文献   
904.
四卡问题的内容促进效应的实验研究   总被引:21,自引:4,他引:17  
张庆林  杨雄 《心理科学》1997,20(4):311-313,,310,
本研究设计了2种抽象材料和4种具体材料的四卡问题,对436名大学生进行测试,以考察被试解决四卡问题时所采用的思维方式并检验命题内容对推理的影响。结果表明,四卡问题十分困难,具体内容的四卡问题并不能产生促进效应,大学生的推理表现出“匹配偏向”的特点。  相似文献   
905.
In a previous study of two-choice reactions, pairings of spatial stimuli with bimanual presses made on a keyboard and verbal stimuli with unimanual aimed movements made on a display screen showed higher set-level compatibility than the opposite pairings; element-level compatibility (i.e., mapping) effects were also larger for the conditions with high set-level compatibility than for those whose set-level compatibility was low. In the 4 experiments described here, the relevant factors were isolated, allowing the determinants of those compatibility differences to be evaluated in more detail. Forty-eight students participated in Experiment 1, and 24 each in Experiments 2, 3, and 4. The primary determinant of the set-level compatibility variation was whether the response alternatives involved 1 or 2 effectors, but the differences in element-level compatibility effects were determined primarily by the distinction between responding on the screen as opposed to on the keyboard. Implications for models of stimulus-response compatibility are examined.  相似文献   
906.
We argue that negotiators' fixed-sum perceptions are caused by the same judgment process that creates false consensus. Bargainers' reliance on their own preferences as a cue to others' preferences leads them to anticipate a fixed-sum conflict. When presented with stereotypic cues, subjects in a negotiating experiment anticipated the variable-sum nature of the task and subsequently realized highly efficient settlements extremely quickly. Surprisingly, even when the party's preferences were unrepresentative of the stereotype, agreements were no less efficient than in the absence of the cue. The implications of these findings for bargaining research and practice are discussed.  相似文献   
907.
A total of 229 late adolescents (a large majority 15 to 19 years of age) completed a questionnaire that assesses a broad range of videogame-relevant experiences, preferences, and attitudes. Videogame playing was found to be a more popular, and a more highly regarded, activity among males than females. Gender differences were also found in participants' ratings of their motivations for playing videogames, their evaluations of particular characteristics of videogames, and their selection of their “most favorite” videogame. The differences between frequent and infrequent videogame players appeared to be limited to differences in the extent to which videogame playing is pursued and evaluated as a positive leisure activity, rather than reflecting broad differences in interest or personality. Some relations were found between participants' self-reported personality characteristics (i.e., self-esteem, empathy, conscientiousness, and introversion) and their attitudes toward videogames.  相似文献   
908.
ABSTRACT It has been hypothesized that individuals who are high on the attribute of self-criticism are particularly vulnerable to failure stress. To test this hypothesis, we examined the relationship between self-criticism and changes in plasma homovanillic acid (HVA; the metabolite of dopamine) and emotion during exposure to an induced-failure task. Participants consisted of 21 women. Plasma HVA and emotion were assessed at three time points: baseline (T1), during stress exposure (T2), and 40 minutes after cessation of the stressor (T3). We found that self-criticism was significantly and positively related to changes in plasma HVA during stress exposure. In addition, the personality attribute was significantly and positively related to subjective ratings of stress and changes in scores on the Confusion-Bewilderment scale of the Profile of Mood States during the task. To our knowledge, this is the first study to report that self-criticism is related to stress-induced changes in biochemistry.  相似文献   
909.
ABSTRACT College students who had yet to marry and begin a family were asked about their desire to have children and their beliefs and expectations about themselves as parents (Study 1) and the characteristics of their prospective children (Study 2). Persons with more avoidant and anxious-ambivalent models of close adult relationships harbored more negative models of parent-hood and parent-child relationships. These findings indicate that working models of parenting and parent-child relationships form well before marriage and the birth of children and that these models are systematically associated with attachment styles in adult relationships. The findings also suggest ways in which insecure attachments between child and parent may be influenced by the caregiver's models of parenting and parent-child relationships.  相似文献   
910.
In the present study, we examined the effects of perceived overqualification on health and the moderating effect of emotional support. Exploratory and confirmatory factor analyses found 2 indicators of perceived overqualification: "mismatch" and "no-grow." Perceived mismatch had a significant negative effect on health but perceived no-grow did not. The main effect revealed that the greater the perceived emotional support, the greater the health. The significant interaction of perceived emotional support and mismatch, and perceived emotional support and no-grow on health indicates that the negative effects of overqualification on health was greater for those perceiving low emotional support than for those perceiving high emotional support. The significance of social support in illuminating the relationship between perceived overqualification and health are discussed.  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