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   22802篇
  免费   968篇
  国内免费   14篇
  2020年   275篇
  2019年   269篇
  2018年   443篇
  2017年   377篇
  2016年   415篇
  2015年   271篇
  2014年   380篇
  2013年   1697篇
  2012年   671篇
  2011年   731篇
  2010年   392篇
  2009年   475篇
  2008年   635篇
  2007年   633篇
  2006年   585篇
  2005年   521篇
  2004年   505篇
  2003年   492篇
  2002年   452篇
  2001年   820篇
  2000年   816篇
  1999年   609篇
  1998年   263篇
  1997年   235篇
  1996年   217篇
  1992年   502篇
  1991年   425篇
  1990年   498篇
  1989年   418篇
  1988年   393篇
  1987年   373篇
  1986年   394篇
  1985年   454篇
  1984年   353篇
  1983年   296篇
  1982年   230篇
  1979年   331篇
  1978年   267篇
  1977年   211篇
  1976年   207篇
  1975年   303篇
  1974年   353篇
  1973年   357篇
  1972年   277篇
  1971年   245篇
  1970年   213篇
  1969年   230篇
  1968年   292篇
  1967年   254篇
  1966年   279篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
Levels and correlates of parental support, peer support, partner support, and/or spiritual support among African American and Caucasian youth were examined in three contexts: adolescent pregnancy (Study 1), first year of college (Study 2), and adolescence and young adulthood (ages 15–29; Study 3). Partially consistent with a cultural specificity perspective, in different contexts different support sources were higher in level and/or more strongly related to adjustment for one ethnic group than the other. Among pregnant adolescents, levels of spiritual support were higher for African Americans than Caucasians; additionally, peer support was positively related to well-being only for African Americans whereas partner support was positively related to well-being only for Caucasians. Among college freshmen, family support was more strongly related to institutional and goal commitment for African Americans than Caucasians; conversely, peer support was more strongly related to institutional and goal commitment among Caucasians. Among 15 to 29-year-olds, levels of parental support and spiritual support were higher among African Americans than Caucasians; additionally, spiritual support was positively related to self-esteem for African Americans but not for Caucasians. Implications and limitations of the research are discussed. The third study was supported by National Institute of Mental Health Grant RO1 MH40963. We thank Monica Greene, Shea Lyda, Wendy Stevenson, and the many undergraduate students who contributed to the three research projects. We also acknowledge the very thoughtful and helpful comments of the anonymous reviewers and the editor, Edison Trickett.  相似文献   
942.
The Americans with Disabilities Act (ADA) of 1990 is the most comprehensive federal civil rights law addressing discrimination against one-fifth of the American population. This article is meant to contribute to the emerging dialogue on ADA implementation by presenting information from a longitudinal investigation of employment integration and economic opportunity under the employment provisions of the ADA, set forth in Title I of the act. The broader relevance of the investigation to emerging questions under Title I law is described. Thereafter, the investigation's seven core findings are presented, and then the implications for future investigation of the ADA are examined.  相似文献   
943.
This study explores the relationship between media use and political commitment. Undergraduate participants answered an extensive political background questionnaire, which included measures of media use, perceived importance of information sources regarding the 1992 presidential election, and various political behaviors as an index of political commitment. Correlational analyses revealed that those who are more politically committed tend to select a variety of media sources regarding a presidential candidate. This study also investigated how informational and commitment variables were related to attitudes towards the major presidential candidates. Results observed for people expressing positive attitudes toward Perot are discussed in terms of the modern day “third party voter.”  相似文献   
944.
The authors examine the influence of cross-cultural training on the racial identity attitudes of 35 White graduate counselors in training (10 men and 25 women) and the impact of gender on training. A pretest-posttest comparison of responses to the White Racial Identity Attitudes Survey (WRIAS) was used. Results indicated that the cross-cultural training course (a) influenced racial identity attitudes of White counselors in training and (b) racial identity attitudes were influenced by gender.  相似文献   
945.
In a series of three experiments, subjects made risky decisions under conditions of hypothetical or real consequences. Task variations across experiments included: (1) type of risk (monetary gambles or investments of time and effort), (2) within-subject and between-subjects manipulations of consequence condition, and (3) single or multiple decisions. The hypothesis of no difference between choices in real and hypothetical consequence conditions was retained in each experiment. Supplemental analyses ruled out various “artifactual” interpretations of the null results. Discussion focused on conditions in which researchers can and cannot infer decision makers’ actual risk preferences from their responses in laboratory tasks.  相似文献   
946.
This study investigated the effectiveness of computer-based training (CBT) versus the standard or traditional lecture method. The study was conducted at a large pharmaceutical manufacturing site located in Eastern North Carolina. Subjects were chemical processors in the bulk chemical production division (N=54). All subjects completed a comprehensive hazardous chemicals safety training program, with one treatment group completing the course via a self-directed computer program (n=27) and one completing the course via traditional instructor-led sessions (n=27). Both delivery formats were identical relative to learning objectives and content. Level of learning was assessed via a 33-item pretest and posttest. Subjects were also administered a 33-item retention test one month following completion of the program. Subject biographical data, including educational level, were collected by questionnaire and the Computer Anxiety Index (CAIN) was administered to assess subjects' level of computer anxiety within the CBT group. Satisfaction with training was assessed in both treatment groups. Results indicated 1) both groups demonstrated significant learning following training, 2) there was no significant difference in level of learning between the two groups, 3) retention after one month was significantly higher in the CBT groups, 4) there was no correlation between educational level or computer anxiety and learning, and 5) there was no significant difference between the two groups on satisfaction with the training experience.  相似文献   
947.
The National Conference of Catholic Bishops has argued for significant government involvement in health care in order to assure respect for what they regard as the right to health care. Critics charge that the bishops are wrong because health care is not a right. In this article, it is argued that these critics are correct in their claim that health care is not a right. However, it is also argued that the premise that health care is not a right does not imply that the market is the most equitable and just system for providing health care. Natural law arguments in the tradition of Roman Catholic social teaching lead to the conclusion that a just and prosperous society has a moral obligation to provide health care even if there is no such right. Further, there are strong moral grounds for concluding that the bishops are correct in their claim that health care ought not to be considered a market commodity. It is argued that if health care ought not to be considered a commodity, then national health insurance is the best available alternative for fulfilling the social obligation to distribute health care resources justly and fairly at this time in American history. The bishops' case for government involvement can be made on the strength of the Catholic tradition in theological argumentation, independent of the claim that health care is a right.  相似文献   
948.
College students periodically experience many challenges in pursuit of their educational goals. Such experiences can have deleterious effects on subsequent motivation and performance when they are perceived as negative. Research shows that some students who experience negative events are buffered against motivational deficits, whereas others are motivationally at-risk. Several individual difference variables have been proposed to account for such diverse reactions. A longitudinal field study that involved three phases was conducted to extend this research. Phase I examined the motivational buffering effects of academic attributional style on students' performance, motivation, and emotions. Results indicated that attributional style related to students' performance, motivation, and emotions. Specifically, students who routinely made unstable and controllable attributions for negative academic events exhibited the greatest performance and motivation compared to students who typically made stable and uncontrollable attributions. Phases II and III were designed to examine the remedial benefits of attributional retraining for different attributional styles. Findings indicated that attributional retraining influenced motivation, emotions, and course grade. These results were qualified by the interaction between attributional style, attributional retraining, and time. Findings are discussed within Weiner's (1985, 1986) attribution theory. This research was based, in part, on the first author's dissertation submitted to the Department of Psychology and the Faculty of Graduate Studies of The University of Manitoba in partial fulfillment for the Degree of Doctor of Philosophy. This research was supported by a Social Sciences and Humanities Research Council of Canada (SSHRCC) doctoral fellowship, a University of Manitoba doctoral fellowship, and a SSHRCC postdoctoral fellowship to the first author. In addition, the research was also supported by a SSHRCC research grant (#410911296) to the second author. The authors gratefully acknowledge the helpful comments of Bernard Weiner, Harvey Keselman, John Adair, Rodney Clifton, and Robert Altemeyer. Also appreciated was the assistance of Verena Menec and the Higher Education Research group.  相似文献   
949.
An injection olfactometer for human psychophysical experiments is described. The olfactometer is capable of presenting, either mono- or birhinally, single odorants and binary mixtures. The pulse form of the olfactory stimulus at the exit of the olfactometer approaches a rectangular form, which makes the olfactometer well suited for olfactory reaction time measurements. Since stimulation periods are independent of the subject’s inhalation, time-intensity measurements over prolonged periods of time are possible as well. In the second part of this paper, a new technique is described for the measurement of the stimulus pulse form at the exit of the olfactometer.  相似文献   
950.
We investigated the ability of subjects to discriminate sugars with a whole-mouth forced-choice paradigm, in which a standard solution was compared with a test solution of varied concentration. Discrimination probabilities were U-shaped functions of test concentration: for 6 subjects and pairwise combinations of fructose, glucose, and sucrose, discriminability always declined to chance over a narrow range of test concentrations. At concentrations ≦ 100 mM, maltose was indiscriminable from fructose but discriminable at higher concentrations for 4 subjects. By analogy with themonochromacy of night vision, whereby any two lights are indiscriminable when their relative intensities are suitably adjusted, we call the gustatory indiscriminability of these sugarsmonogeusia. The simplest account of monogeusia is that all information about the indiscriminable sugars is represented by a single neural signal that varies only in magnitude. The discriminability of maltose from the other sugars at higher concentrations is consistent with the hypothesis that maltose also activates a second gustatory code.  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