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   47335篇
  免费   960篇
  国内免费   12篇
  2019年   285篇
  2018年   3796篇
  2017年   3159篇
  2016年   2631篇
  2015年   478篇
  2014年   474篇
  2013年   2246篇
  2012年   1270篇
  2011年   3158篇
  2010年   2952篇
  2009年   1947篇
  2008年   2341篇
  2007年   2836篇
  2006年   648篇
  2005年   789篇
  2004年   743篇
  2003年   644篇
  2002年   678篇
  2001年   828篇
  2000年   854篇
  1999年   629篇
  1998年   361篇
  1997年   332篇
  1993年   294篇
  1992年   539篇
  1991年   472篇
  1990年   509篇
  1989年   482篇
  1988年   458篇
  1987年   467篇
  1986年   465篇
  1985年   477篇
  1984年   409篇
  1983年   373篇
  1982年   324篇
  1981年   287篇
  1979年   460篇
  1978年   374篇
  1977年   344篇
  1976年   303篇
  1975年   434篇
  1974年   450篇
  1973年   409篇
  1972年   376篇
  1971年   335篇
  1970年   305篇
  1969年   348篇
  1968年   386篇
  1967年   347篇
  1966年   352篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Sperling, Landy, Dosher, and Perkins (1989) proposed an objective 3D shape identification task with 2D artifactual cues removed and with full feedback (FB) to the subjects to measure KDE and to circumvent algorithmically equivalent KDE-alternative computations and artifactual non-KDE processing. (1) The 2D velocity flow-field was necessary and sufficient for true KDE. (2) Only the first-order (Fourier-based) perceptual motion system could solve our task because the second-order (rectifying) system could not simultaneously process more than two locations. (3) To ensure first-order motion processing, KDE tasks must require simultaneous processing at more than two locations. (4) Practice with FB is essential to measure ultimate capacity (aptitude) and, thereby, to enable comparisons with ideal observers. Experiments without FB measure ecological achievement--the ability of subjects to extrapolate their past experience to the current stimuli.  相似文献   
992.
It has been suggested that family satisfaction can be measured by having a person complete the Family Adaptability and Cohesion Evaluation Scale (FACES-II) twice: once as the person essentially sees the family (actual version), and once as they wish the family to be (ideal version). The discrepancy between the actual and ideal scores is contended to be a measure of satisfaction with family. Though conceptually attractive, this measurement strategy was not verified, as assessed in the present study by correlating the actual-ideal discrepancy scores with family discord (Index of Family Relations) scores. Clinical adoption of the actual-ideal discrepancy-score as a measure of family satisfaction is thus seen as premature, until more supportive evidence is demonstrated.  相似文献   
993.
Compared four treatment conditions to test their ability to enhance compliance with vascular access cleansing (VAC) procedures in a group of 56 hemodialysis patients. The conditions were patient education, behavioral management with monetary incentive, patient education/behavioral management, and attention control. Behavioral observers rated VAC behavior at pretreatment, posttreatment 1-month follow-up, and 1-year follow-up. Knowledge of VAC procedures was also assessed via a questionnaire at pretreatment and posttreatment. Data were analyzed using repeated-measures multivariate analyses of variance. Results indicated that the patients in the education/behavioral, behavioral, and education groups gave significantly more correct answers on our VAC knowledge questionnaires at posttreatment than did patients in the attention control group. Further, patients in the education/behavioral and behavioral groups completed significantly more VAC steps at posttreatment and 1-month follow-up than did patients in the education group and in the attention control group. Differences were not maintained at 1-year follow-up, although more than 50% of the patients were lost to follow-up. Implications of the present findings for behavioral and educational interventions are discussed.  相似文献   
994.
The present study used a multitrait-multimethod technique [D.T. Campbell and D. W. Fiske (1959) “Convergent and Discriminant Validation by the Multitrait-Multimethod Matrix,” Psychological Bulletin, 56, 81–105] to examine Bem's [(1974) “The Measurement of Psychological Androgyny,” Journal of Consulting and Clinical Psychology, 42, 152–162] use of an instrumental-expressive dichotomy to conceptualize the Masculinity and Femininity scales of the Bem Sex Role Inventory as statistically orthogonal constructs. Results indicate that while perhaps reliable, masculinity and femininity lack clear convergent and discriminant validity. Therefore, Bem's contention that masculinity and femininity are orthogonal constructs is questioned. Results are discussed in light of trait- vs. method-driven research.  相似文献   
995.
Towards a general theory of representation   总被引:3,自引:0,他引:3  
Summary The models of science are representations of a part of reality. Every science has its own specific rules of constructing models, but there are many common rules that must be followed. These rules are to be part of what may be called a general theory of representation. This paper discusses some general aspects of representation that must be considered before such a general theory can be created. There are five sections: (1) an introduction to the topic of representation in general; (2) an overview of some general types of representation, such as goal-directed and self-organizational representations; (3) a short discussion of representation in some specific disciplines; (4) some formal aspects of representations; and (5) a discussion of epistemological aspects of representation, especially scientific reduction and mental causation.This paper was written during participation in the Research Project Mind and Brain, at the Centre for Interdisciplinary Research, University of Bielefeld, BRD.  相似文献   
996.
Two experiments were performed to assess the accuracy and precision with which adults perceive absolute egocentric distances to visible targets and coordinate their actions with them when walking without vision. In experiment 1 subjects stood in a large open field and attempted to judge the midpoint of self-to-target distances of between 4 and 24 m. In experiment 2 both highly practiced and unpracticed subjects stood in the same open field, viewed the same targets, and attempted to walk to them without vision or other environmental feedback under three conditions designed to assess the effects on accuracy of time-based memory decay and of walking at an unusually rapid pace. In experiment 1 the visual judgments were quite accurate and showed no systematic constant error. The small variable errors were linearly related to target distance. In experiment 2 the briskly paced walks were accurate, showing no systematic constant error, and the small, variable errors were a linear function of target distance and averaged about 8% of the target distance. Unlike Thomson's (1983) findings, there was not an abrupt increase in variable error at around 9 m, and no significant time-based effects were observed. The results demonstrate the accuracy of people's visual perception of absolute egocentric distances out to 24 m under open field conditions. The accuracy of people's walking without vision to previously seen targets shows that efferent and proprioceptive information about locomotion is closely calibrated to visually perceived distance. Sensitivity to the correlation of optical flow with efferent/proprioceptive information while walking with vision may provide the basis for this calibration when walking without vision.  相似文献   
997.
The kinds of messages teachers give students regarding the value of credentials in the job-getting package during a period of high youth unemployment are explored. The response made by students to the credentialling ideology promoted in schools, and their construction of the job-getting formula, are also described. The validity of the two versions of job-getting strategies is considered in the light of evidence provided by a number of empirical research projects. The superiority of student knowledge in this area is used to present a case for a critical and democratic education which appropriates and legitimises the student voice.  相似文献   
998.
Cann  Arnie  Siegfried  William D. 《Sex roles》1990,23(7-8):413-419
Research has consistently found that effective leadership is perceived as characterized by traits similar to those associated with masculine gender roles. These perceptions would appear to be at odds with extensive research indicating that effective leadership requires consideration and structuring behaviors—behaviors that seem to represent both masculine and feminine styles. In two separate studies, the correspondence between gender stereotypes and dimensions of effective leadership were assessed. Results indicate that consideration behaviors are perceived to be feminine, while structuring behaviors are perceived to be masculine. Similarly, qualities that characterize the masculine gender role are perceived to be consistent with structuring, while qualities associated with the feminine gender roles are perceived to be consistent with consideration. It is suggested that an increased awareness of the androgynous nature of effective leadership behaviors might weaken the biases in favor of male leaders.  相似文献   
999.
Are women in a female-dominated profession more successfully able to combine work and family obligations than women in a male-dominated profession? To explore this question, a comparison was made between the family status and careers of 747 women librarians (a female-dominated profession) and those of 449 women MBAs (a male-dominated profession). It was expected that the librarians would marry earlier and have more children. This general prediction was not supported. Over half of both groups of women were married, and after controlling for age, there were no differences in number of children. However, many women without children in both groups reported that they would like to be mothers. This disparity between wanting children and not having them was more common for women MBAs than women MLSs. MBAs and librarians were about equally likely to have had job interruptions, but librarians were more likely to have worked part-time. Reasons for an interruption to full-time work were as likely to be for problems finding (full-time) work as for family responsibilities. Librarians' salaries were much lower, but job interruptions and part-time work had a more negative effect on the salaries of women in business. In sum, the data suggest that many of the women surveyed have not combined motherhood with a professional career and that it is probably somewhat more difficult to combine a family with a career in business than with a career in library science.  相似文献   
1000.
Feigned insanity in nineteenth-century America is appraised through a review of the medical and legal literature. The authors focus on the explanations for feigning, procedures used in uncovering feigning, and the role of feigning in the courtroom. This discussion of feigned insanity demonstrates the remarkable consistency of approach to this form of malingering over the past 200 years.  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