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   7505篇
  免费   404篇
  国内免费   4篇
  2023年   90篇
  2022年   133篇
  2021年   166篇
  2020年   231篇
  2019年   206篇
  2018年   393篇
  2017年   387篇
  2016年   341篇
  2015年   209篇
  2014年   255篇
  2013年   994篇
  2012年   561篇
  2011年   558篇
  2010年   351篇
  2009年   220篇
  2008年   449篇
  2007年   360篇
  2006年   312篇
  2005年   257篇
  2004年   175篇
  2003年   179篇
  2002年   155篇
  2001年   80篇
  2000年   105篇
  1999年   59篇
  1998年   38篇
  1997年   32篇
  1996年   26篇
  1995年   24篇
  1994年   19篇
  1993年   27篇
  1992年   35篇
  1991年   36篇
  1990年   31篇
  1989年   31篇
  1988年   34篇
  1987年   22篇
  1986年   16篇
  1985年   22篇
  1984年   21篇
  1983年   14篇
  1979年   20篇
  1976年   14篇
  1973年   13篇
  1972年   14篇
  1971年   16篇
  1969年   12篇
  1968年   17篇
  1966年   16篇
  1965年   16篇
排序方式: 共有7913条查询结果,搜索用时 15 毫秒
81.
The purpose of this paper is to evaluate the significance of the existential notion of authenticity for medical ethics. This is done by analyzing authenticity and examining its implications for the patient-professional relationship and for ethical decision-making in medical situations. It is argued that while authenticity implies important demand for individual responsibility, which has therapeutic significance, it perpetuates ideas which are antithetical both to authentic interaction between patients and professionals and to fruitful deliberation of moral dilemmas. In order to counteract these consequences, an alternative idea of authenticity is introduced. According to this idea, authenticity is not regarded primarily as individual sovereignty, but as an ability to participate in a dialogue in which the subjectivity of both partners is respected. Such practice, based on mutual trust and responsibility, would enhance common decision-making and overcome the alienation between patients and professionals.  相似文献   
82.
Musically trained and untrained subjects (N=30) were asked to synchronize their finger tapping with stimuli in auditory patterns. Each pattern comprised six successive tonal stimuli of the same duration, the first of which was accented by a different frequency. The duration of interstimulus onset intervals (ISIs) gradually increased or decreased in constant steps toward the end of the patterns. Four values of such steps were used in different trials: 20, 30, 45, and 60 msec. Various time-control mechanisms are hypothesized as being simultaneously responsible for subjects’ incorrect reproduction of the internal temporal ratios of the stimulus patterns. The mechanism of assimilation (of a central tendency) led subjects to enforce a regular (isochronous) structure on the patterns. The influence of other time-control mechanisms (distinction, subjective expression of an accent, sequential transfer) was expressed mainly in differences between intertap onset intervals (ITIs) and the corresponding ISIs at the beginning of the patterns. The duration of the first two ITIs was in the majority of the trials in an inverse ratio to the ratio of the respective ISIs. The distortions resulting from the timing mechanisms concerned were more pronounced in the performance of nonmusicians than in that of musicians.  相似文献   
83.
Effects of the similarity between target and distractors in a visual search task were investigated in several experiments. Both familiar (numerals and letters) and unfamiliar (connected figures in a 5 × 5 matrix) stimuli were used. The observer had to report on the presence or absence of a target among a variable number of homogeneous distractors as fast and as accurately as possible. It was found that physical difference had the same clear effect on processing time far familiar and for unfamiliar stimuli: processing time decreased monotonically with increasing physical difference. Distractors unrelated to the target and those related to the target by a simple transformation (180° rotation, horizontal or vertical reflection) were also compared, while the physical difference was kept constant. For familiar stimuli, transformational relatedness increased processing time in comparison with that fort unrelated stimulus pairs. It was further shown in a scaling experiment that this effect could be accounted for by the amount of perceived similarity of the target-distractor pairs. For unfamiliar stimuli, transformational relatedness did have a smaller and less pronounced effect. Various comparable unrelated distractors resulted in a full range of processing times. Results from a similarity scaling experiment correlated well with the outcome of the experiments with unfamiliar stimuli. These results are interpreted in terms of an underlying continuum of perceived similarity as the basis of the speed of visual search, rather than a dichotomy of parallel versus serial processing.  相似文献   
84.
85.
Empirically defined scales of depressive, attention deficit hyperactivity disorder, oppositional-defiant disorder, and conduct symptoms from the lay-administered National Institute of Mental Health (NIMH) Diagnostic Interview Schedule for Children (DISC), version 2.3, and evidence of their reliability and validity, are presented. The scales were developed using factor analyses of data obtained from an epidemiologic survey of over 1,200 children drawn from four sites across the U.S. and Puerto Rico (the NIMH Methods for the Epidemiology of Child and Adolescent Mental Disorders, or MECA Study). Their psychometric properties were tested in a subsample of children reinterviewed by clinicians. The findings support the use of these continuous measures. The scales are strongly related to the diagnostic categories and show good test-retest reliability. The scales can be used to characterize severity in children with diagnoses and to describe problems and symptoms in children without diagnoses. Because these scales can measure gradations in symptomatology, they may be more useful than categorical measures. Like categorical measures, the scales based on the DISC are greatly influenced by the informant, whether child or parent.This research was supported by grant MH-46732 from the National Institute of Mental Health, Bethesda, Maryland.The MECA Program is an epidemiologic methodology study performed by four independent research teams in collaboration with staff of the Division of Clinical Research, which was reorganized in 1992 with components now in the Division of Epidemiology and Services Research and the Division of Clinical and Treatment Research, of the NIMH, Rockville, Maryland. The NIMH Principal Collaborators are Darrel A. Regier, MD, MPH, Ben Z. Locke, MSPH, Peter S. Jensen, MD, William E. Narrow, MD, MPH, and Donald S. Rae, MA; the NIMH Project Officer was William J. Huber. The Principal Investigators and Coinvestigators from the four sites are as follows: Emory University, Atlanta, Georgia, UO1 MH46725: Mina K. Dulcan, MD, Benjamin B. Lahey, PhD, Donna J. Brogan, PhD, Sherryl Goodman, PhD, and Elaine Flagg, PhD; Research Foundation for Mental Hygiene at New York State Psychiatric Institute (Columbia University), New York, New York, UO1 MH46718: Hector R. Bird, MD, David Shaffer, MD, Myrna Weissman, PhD, Patricia Cohen, PhD, Denise Kandel, PhD, Christina Hoven, PhD, Mark Davies, MPH, Madelyn S. Gould, PhD, and Agnes Whitaker, MD; Yale University, New Haven, Connecticut, UO1MH46717: Mary Schwab-Stone, MD, Philip J. Leaf, PhD, Sarah Horwitz, PhD, and Judith H. Lichtman, MPH; University of Puerto Rico, San Juan, Puerto Rico, UO1 MH46732: Glorisa Canino, PhD, Maritza Rubio-Stipec, MA, Milagros Bravo, PhD, Margarita Alegría, PhD, Julio Ribera, PhD, Sarah Huertas, MD, and Michael Woodbury, MD.The authors gratefully acknowledge Zenaida González and José Martínez who performed the data nalayses, as well as Elizabeth Pastrana, and Felícita Laboy, secretaries, for their valuable contributions to this work.  相似文献   
86.
This study was designed to examine the relationship between gender role orientation and psychological adjustment during pregnancy and the postpartum period in a large sample of French-speaking Caucasian mothers. Gender role was assessed with the Bem Sex Role Inventory, which classifies subjects into four categories: androgynous, masculine, feminine, and undifferentiated. A discriminant analysis showed a relationship between androgyny and the following measures of psychological adaptation: self-esteem, satisfaction with social support, and level of apprehension toward perinatal stressors. The masculine gender role was linked with self-esteem, work involvement, age, and severity of perinatal stress. No relationship was found between gender role and the level of antenatal or postnatal depressive symptomatology. Stress, marital support, and social support were among the predictors of postpartum depression, which underlined the importance of taking these variables into account when studying the well-being of mothers during the postnatal period. Results are discussed in light of previous literature on the association between gender role and motherhood. The limitations of Bem's model and inventory are also considered.  相似文献   
87.
This article presents an approach we have developed for the assessment of public research institutions in the natural sciences and engineering. The method consists in the exploitation of available S&T databases and indicators, including bibliometrics (databases of scientific as well as technical literature), patents, and internal data. Results are therefore derived through multiple databases. The objective is to profile a specific national R&D community in order to assess the positioning of a public institution or program within the community to which it belongs. It involves obtaining the profile of the evolution of an R&D area, the R&D performers, the financing and support institutions, the users of R&D results, and the interactions between all these actors. A case-study of Canadian research in polymers is presented. Part of this research was financed by the National Research Council of Canada, and by a strategic grant from the Social Sciences and Humanities Research Council. The research benefited from the expertise of Robert Letellier, Robert H. Marchessault, Jacques Martel, and Marielle Piché, and from the technical assistance of Maryse Prud’homme, Marcel Parent, and Benoit Longpré.  相似文献   
88.
The purpose of the present research was to propose and test a motivational process model of academic achievement. The model posits that parental, teachers, and school administration support for students' autonomy positively influences students' perceived school competence and autonomy. In turn, perceived school competence and autonomy affect positively self-determined school motivation which in turn influences academic achievement. Two studies using a prospective design tested the adequacy of the model. In Study I, participants were 1,623 ninth-grade students. Results from structural equation modeling supported the motivational model. Participants in Study 2 were 1,098 tenth-grade students. Results from this study corroborated those of Study 1 controlling for students' prior achievement in the ninth grade. The role of self-determinod school motivation in academic achievement is discussed and avenues for future research are considered. This research is part of a larger project that is being funded by grants from the William and Flora Hewlett Foundation; the San Francisco Foundation; the Robert Wood Johnson Foundation; the Danforth Foundation; the Smart Foundations; the Pew Charitable Trusts; the John D. and Catherine T. MacArthur Foundation; the Annenberg Foundation; Spunk Fund, Inc.; the DeWitt Wallace-Reader's Digest Fund, Inc.; Louise and Claude Rosenberg; and the Center for Substance Abuse Prevention, U.S. Department of Health and Human Services. The views expressed in the paper are those of the authors and not necessarily of the funders. We are grateful to the many educators, students, and colleagues who cooperated with us on this project and to several anonymous reviewers who provided helpful suggestions.  相似文献   
89.
90.
The purpose of this clinical experiment was to investigate the manipulability of a Factor II avoidance response (arm movement). The substantive hypothesis under test was that its suppression would be enhanced by repeated punishment sessions. During the first of nine therapy sessions response-contingent negative stimulation was not delivered. In the next five, after a base-rate period, “wrong” was made consequent upon the target response. In each of these sessions the suppression of arm movement was apparent. However, the magnitude of the suppression decreased from session to session. Evidently, the continued use of punishment did not enhance suppression. Because of this finding procedural changes were introduced in the next three therapy sessions. Verbal praise was added as a consequence of increasingly stringent omission criteria and three consecutive units of praise led to time-out from the reportedly fatiguing task of continuous speech. A marked reduction and then complete extinction resulted. Moreover, learning was evidenced since the frequency of arm movement lessened in the base-rate period of each session.  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