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   48529篇
  免费   1067篇
  国内免费   107篇
  2020年   330篇
  2019年   351篇
  2018年   3773篇
  2017年   3146篇
  2016年   2667篇
  2015年   560篇
  2014年   512篇
  2013年   2271篇
  2012年   1334篇
  2011年   3124篇
  2010年   2951篇
  2009年   1956篇
  2008年   2381篇
  2007年   2770篇
  2006年   643篇
  2005年   800篇
  2004年   703篇
  2003年   652篇
  2002年   619篇
  2001年   782篇
  2000年   760篇
  1999年   524篇
  1998年   297篇
  1997年   277篇
  1992年   496篇
  1991年   474篇
  1990年   484篇
  1989年   475篇
  1988年   438篇
  1987年   439篇
  1986年   467篇
  1985年   504篇
  1984年   428篇
  1983年   393篇
  1982年   289篇
  1981年   325篇
  1979年   458篇
  1978年   344篇
  1977年   302篇
  1976年   287篇
  1975年   422篇
  1974年   477篇
  1973年   500篇
  1972年   423篇
  1971年   414篇
  1970年   386篇
  1969年   408篇
  1968年   499篇
  1967年   478篇
  1966年   459篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
Experiment 1 replicated Yaniv and Meyer's (1987) finding that lexical decision and episodic recognition performance was better for words previously yielding high-accessibility levels (a combination of feeling-of-knowing and tip-of-the-tongue ratings) in comparison with those yielding low-accessibility levels in a rare word definition task. Experiment 2 yielded the same pattern even though lexical decisions preceded accessibility estimates by a full week. Experiment 3 dismissed the possibility that the Experiment 2 results may have been due to a long-term influence from the lexical decision task to the rare word judgment task. These results support a model in which Ss (a) retrieve topic familiarity information in making accessibility estimates in the rare word definition task and (b) use this information to modulate lexical decision performance.  相似文献   
22.
23.
OBJECTIVE: To test a theoretical model of how ethnic pride and self-control are related to risk and protective factors. DESIGN: A community sample of 670 African American youth (mean age = 11.2 years) were interviewed in households. MAIN OUTCOME MEASURES: Measures of cigarette smoking, alcohol use, and sexual behavior (lifetime to past month). RESULTS: Structural modeling analyses indicated parenting was related to self-control and self-esteem, and racial socialization was related to ethnic pride. Self-control and self-esteem variables were related to levels of deviance-prone attitudes and to perceptions of engagers in, or abstainers from, substance use and sexual behavior. The proximal factors (behavioral willingness, resistance efficacy, and peer behavior) had substantial relations to the criterion variables. Participant gender and parental education also had several paths in the model. Results were generally similar for the 2 outcome behaviors. CONCLUSIONS: In this population, self-esteem and self-control are related to parenting approaches and have pathways to attitudes and social perceptions that are significant factors for predisposing to, or protecting against, early involvement in substance use and sexual behavior.  相似文献   
24.
Most studies of suicide in younger patients have demonstrated significant alterations in the serotonin system. Although a high percentage of completed suicides occur in late-life, to date very few studies of the biology of suicide have focused on this age group. This chapter describes age-related changes in the central nervous system pertinent to the biology of suicide, then reviews post-mortem biological studies of the brains of suicides and suicide attempters. As suicide attempts in the elderly are characterized by the use of violent means, biologic studies of impulsive violence are discussed. Finally we describe data on the effect of degenerative diseases on the serotonin system and the possible link to increased suicidal behavior in affected patients. This review underscores the need for further study of the biology of suicide in the geriatric age group.  相似文献   
25.
26.
27.
Two experiments examine the effect of multiple synthetic voices in an e‐commerce context. In Study 1, participants (N= 40) heard five positive reviews about a book from five different synthetic voices or from a single synthetic voice. Consistent with the multiple source effect, results showed that participants hearing multiple synthetic voices evaluated the reviewed books more positively, predicted more favorable public reaction to the books, and felt greater social presence of virtual speakers. The effects were mediated by participants’ feelings of social presence. The second experiment (N= 40) showed that the observed effects persisted even when participants were shown the purely artificial nature of synthesized speech. These results support the idea that characteristics of synthetic voices in doubly disembodied language settings influence participants’ imagination of virtual speakers, and that technological literacy does not hinder social responses to anthropomorphic technologies such as text‐to‐speech (TTS).  相似文献   
28.
29.
In a communication process that involves a target subject (what is being communicated about) and a source, existing attitudes (positive or negative) toward the target or the source influence communication effects. People also may hold ambivalent attitudes (positive and negative) toward the target or the source, but the implications of such ambivalent attitudes on communication effects remain unclear in communication research. This study tries to fill that void by exploring ambivalent attitudes toward the target and source on communication effects and proposing an integrated model to demonstrate that ambivalent attitudes encourage systematic processing (Experiments 1 and 2) and that identification with the target or the source further encourages motivated processing among ambivalent people (Experiments 3 and 4).  相似文献   
30.
It is widely assumed that reinforcers are biologically relevant stimuli, or stimuli that have been associated with biologically relevant stimuli. However, brief, arbitrary stimuli have also been reported to have reinforcement-like effects, despite being unrelated to biologically relevant stimuli like food. The present study explored the potential reinforcement-like effects of brief stimuli across 5 experiments. In Experiments 1 through 4, pigeon subjects responded for food reinforcement and brief stimulus presentations in a 2-component multiple schedule. Neither baseline response rates nor resistance to change during disruption tests were systematically greater in a component with versus without brief stimulus presentations. Increasing the rate and duration of brief stimulus presentations in Experiment 4 did not reveal reinforcement-like effects when compared directly with food. In Experiment 5, pigeons chose between independent terminal links in a concurrent-chains procedure. Across conditions, varying the location, duration, and rate of brief stimulus presentations in the terminal links had no systematic effects on preference. In contrast, varying rates of food reinforcers resulted in large and reliable shifts in preference. Therefore, the present study found no systematic evidence that brief stimuli unrelated to food reliably increase response rates, resistance to change, or preference. These data demonstrate the value of systematic replication, and a behavioral momentum approach to assessing potential reinforcement-like effects.  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