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   52357篇
  免费   2104篇
  国内免费   30篇
  54491篇
  2020年   597篇
  2019年   746篇
  2018年   1072篇
  2017年   1076篇
  2016年   1125篇
  2015年   748篇
  2014年   920篇
  2013年   4561篇
  2012年   1671篇
  2011年   1810篇
  2010年   1058篇
  2009年   1069篇
  2008年   1642篇
  2007年   1624篇
  2006年   1425篇
  2005年   1303篇
  2004年   1263篇
  2003年   1145篇
  2002年   1195篇
  2001年   1754篇
  2000年   1649篇
  1999年   1265篇
  1998年   665篇
  1997年   571篇
  1996年   514篇
  1995年   520篇
  1994年   494篇
  1993年   515篇
  1992年   1010篇
  1991年   953篇
  1990年   940篇
  1989年   850篇
  1988年   813篇
  1987年   802篇
  1986年   803篇
  1985年   853篇
  1984年   668篇
  1983年   579篇
  1982年   471篇
  1979年   655篇
  1978年   488篇
  1976年   447篇
  1975年   589篇
  1974年   620篇
  1973年   594篇
  1972年   539篇
  1971年   473篇
  1968年   539篇
  1967年   540篇
  1966年   475篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
171.
172.
A hardware-and-software system is described that permits musical-bandwidth signal quantization, monophonic or stereophonic, direct to/from hard disk. The system, which uses an IBM AT or compatible, is cost effective and device independent. Software functions allow for automated aural and graphical signal analyses. Perceptual experiments that use contextual, natural-instrument stimuli, and that take advantage of the immediate and random access provided by this system, are described.  相似文献   
173.
This paper develops hypotheses about the implications of different types of decision for the utilization of different types of systematically produced information: data, research, and analysis. The engineering and enlightenment models found in the knowledge utilization literature prove inadequate for this purpose. We turn to three decision models—routine, incremental, and fundamental–and determine their implied demands for information. We also examine how information might be used in scanning procedures in anticipation of decision regime shifts. The results suggest that patterns of information should differ markedly in each decision context and indicate that there may be an inherent bias against the use of research in decision. Evert A. Lindquist, a doctoral candidate at the Graduate School of Public Policy, University of Calfornia at Berkeley, is completing a dissertation onPolicy Institutes in Canada: The Organization and Relevance of Public Inquiry and will join the faculty of the Department of Political Science at the University of Toronto this fall. Organizations, public policy, and the role of information in decision making are among his primary research interests.  相似文献   
174.
We outline a BASIC program and subsidiary machine language timing routines that enable the Apple II series of computers to be employed as control devices for the tachistoscopic presentation of 35-mm slides and the collection of response latencies. The program is functional for experiments that require pictorial stimuli to be presented in up to three separate fields, with precise display times, precise interstimulus and intertriai intervals, and the collection of manual or vocal reaction times with millisecond accuracy. The major advantages of this system are that initial setup costs are substantially lower than those for other similar systems (e.g., Loftus, Gillispie. Tigre, & Nelson, 1984) and that user customization of the program may be accomplished by anyone possessing rudimentary knowledge of the BASIC programming language.  相似文献   
175.
A unique relationship exists between physicians and philosophers — one that expands on the constructive potential of the liaison between physicians and, for example, theologians, on the one hand, or, social workers on the other. This liaison should focus in the scientific aspects of medicine, not just the ethical aspects. Philosophers can provide physicians with a perspective on both the philosophy and the history of medicine through the ages — a sense of how medicine has adapted to the social cultural and ethical needs of each period. This perspective, while emphasizing medicine asscience, should not be limited to matters of methodology, or to criteria for distinguishing science from other intellectual pursuits, but should be concerned also with the history, sociology and politics of science. Both physicians and philosophers stand to gain from a strengthening of their active liaison now as never before; but most of all, the public will be the beneficiary.  相似文献   
176.
177.
S Oz  A Tari  M Fine 《Adolescence》1992,27(105):193-202
Two projective techniques were employed to explore the psychological characteristics of teenage mothers who were found, in a previous study, to have experienced more traumatic childhoods than the nonmother control group. Part I, presented here, investigated ego development using the Loevinger Sentence Completion Test. (Part II, responses to a set of TAT cards, will appear in a subsequent issue of Adolescence.) In comparison with the nonmothers, teenage mothers demonstrated more mature ego development. This is in distinct contrast with most reports in the literature, and the ramifications of these results are discussed. In addition, content analyses of the responses to the Sentence Completion Test confirm the highly involved mother-daughter and negative father-daughter relationships found in the previous study with this sample.  相似文献   
178.
S A Sharlin  M Mor-Barak 《Adolescence》1992,27(106):387-405
This paper deals with girls aged 13 to 21 who have run away from home. Social workers who work with such girls point out that they are not a homogeneous population and that their motives can be very different. This study divides their motives for running away into two types, "running from" and "running to," and describes the specific personality traits associated with each. Findings indicate that girls who "run to" are younger, more impulsive, have an internal locus of control and a history of more runaways and longer periods of staying away from home. Girls who "run from," on the other hand, are older, more reflective, have an external locus of control and a history of fewer runaways and shorter periods away from home.  相似文献   
179.
Our goal was to test whether current hemisphere predominance is a predictor of scores on standardized measures of personal optimism and preference for risk. In two between-subject experiments, current hemisphere predominance was measured by the direction and extent of line bisecting errors. Pearson correlations and median splits of the line bisecting errors showed significantly greater personal optimism and preference for risk with left hemisphere predominance. These results support previous research in which manipulation of hemisphere predominance produced similar effects on personal optimism in normal individuals and on risk taking in lesioned and normal samples. We conclude that the association of optimism and risk with left hemisphere predominance can be observed in resting as well as in manipulated situations.  相似文献   
180.
Seventh-grade students and teachers from twenty-three middle and junior high schools were surveyed to determine the association between teacher attitudes, behavioral intentions, and smoking behavior and the prevalence of student smoking. Teacher attitudes toward smoking policies were found to be strongly related to the current smoking behavior of the teacher but not consistently related to student smoking. In addition, teacher likelihood of intervening showed a modest association with teacher smoking status, with current smokers generally indicating being the least likely to intervene for student possession or use of cigarettes. Teacher intentions to intervene were strongly associated with the prevalence of smoking among boys but not girls.  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