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   21140篇
  免费   91篇
  国内免费   113篇
  2024年   3篇
  2023年   13篇
  2022年   18篇
  2021年   20篇
  2020年   31篇
  2019年   31篇
  2018年   3506篇
  2017年   2839篇
  2016年   2267篇
  2015年   204篇
  2014年   109篇
  2013年   127篇
  2012年   602篇
  2011年   2446篇
  2010年   2554篇
  2009年   1512篇
  2008年   1758篇
  2007年   2246篇
  2006年   87篇
  2005年   275篇
  2004年   205篇
  2003年   138篇
  2002年   79篇
  2001年   47篇
  2000年   66篇
  1999年   29篇
  1998年   27篇
  1997年   21篇
  1996年   15篇
  1995年   9篇
  1994年   8篇
  1993年   6篇
  1992年   6篇
  1991年   4篇
  1990年   10篇
  1989年   2篇
  1986年   2篇
  1985年   2篇
  1984年   3篇
  1982年   2篇
  1980年   1篇
  1979年   2篇
  1977年   1篇
  1976年   2篇
  1975年   2篇
  1974年   2篇
  1973年   1篇
  1969年   1篇
  1968年   1篇
  1931年   1篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
91.
We studied the effects of expectation and repetition on searching for singletons in very brief displays. In Experiment 1, we found that when a given feature defined the singleton for a whole block--so that in every trial the subject could expect a particular target feature--search accuracy was significantly higher than when the feature setting was randomly redetermined from trial to trial. However, an unexpected repetition triggered almost no advantage. In Experiment 2, we found no advantage for expected alternation. Experiments 3 and 4 demonstrated that there is little or no advantage for perception in conditions allowing only for target-feature facilitation or distractor-feature inhibition. We propose that in singleton search a division of feature space facilitates detection, and that this division works best under conditions of expected repetition. Experiment 5 replicated Experiment 1, but in Experiment 5 we examined response times and long display exposures. Results suggested that previous findings of singleton priming reflect mainly postperceptual factors.  相似文献   
92.
The Russian Jewish intellectual, Chaim Zhitlovsky (1865–1943), a leading architect of secular Jewish culture and thought, was a central figure in the progressive Jewish intelligentsia of the late nineteenth and early twentieth century. In an essay written in 1927, Yidn un Yiddishkayt (Jews and Jewishness), he sought to define the secular essence of what he calls Yiddishkayt. This essay is not the first in Zhitlovskys long publicistic career in which he searches for new, secular definitions of Jewish identity and culture. But this essay differs, since it is marked by Zhitlovskys use of contemporary social scientific notions of race and racial traits to conceptualize what he believes constitutes Jewishness in a non-religious context, along with his adoption of the mystical Jewish concept of the pintele yid, the theory of an innate Jewishness embodied by a Jewish spark. Zhitlovskys desire to craft a truly secular theory of Jewish identity led him ironically to accept models of Jewish identity at odds with his stated larger vision. In turning to contemporary racial theory, as well as long nurtured mystical models of Yiddishkayt, Zhitlovsky reveals the wide range of ideological discourses that led him to innovative and controversial notions of modern Jewish identity.  相似文献   
93.
青少年性发展的差异及其对人格发展的影响   总被引:2,自引:0,他引:2  
研究青少年性发育现状及其对性心理与人格发展的影响。方法:采用统一编制的《中学生性现状调查问卷》及16PF人格问卷,采用分层抽样方法,对江西4所中学的1000名学生进行问卷调查。结果:(1)青少年手淫行为发生率、与异性交往愿望及性冲动等方面均存在性别差异和年级差异;(2)性成熟的青少年的多种人格特征与未成熟的存在显著性差异。结论:青少年性生理发育正常,但在性心理方面很不成熟,对手淫、性冲动和异性交往等方面问题较多,性发展影响青少年人格发展。  相似文献   
94.
This paper presents a multinomial logit analysis of the methods used by Taiwanese individuals who completed suicide between 1991 and 1993. We investigated the influence of age, gender, urban or rural residence, seasons, and occupations on the six "choices" of suicide methods. The findings suggest that a systematic pattern exists between the choice of method and demographic characteristics of persons who have completed suicide. Most of the different patterns of suicide by sex, age, occupation, or residence can be understood by the different availability and accessibility to the means of suicide faced by the individuals. Our findings support Becker's (1962, 1974, 1993) contention that all kinds of human behavior or choices are shaped by the constraints imposed on the individuals. The findings also have important policy implications for suicide prevention in that they support Lester's advocacy to prevent or reduce suicide incidents by limiting availability, blocking accessibility, or "inconveniencing" the suicidal individuals.  相似文献   
95.
Throughout the U.S., state laws require professionals who work with children to report cases of suspected child abuse to child protection services. Both practically and conceptually, however, significant problems arise from a lack of clarity regarding the threshold that has been set for reporting. Specifically, there is no consensus as to what constitutes reasonable suspicion, and little direction for how mandated reporters should gauge their legal and professional responsibilities when they harbor suspicion. In this paper we outline the context of the problem, discuss the nature and scope of its conceptual underpinnings, and offer recommendations for moving towards a concrete, practical solution.  相似文献   
96.
Previous researchers have proposed that there are two types of symmetry detection: one based on crude preattentive symmetry judgments and another based on detailed scrutiny of individual parts (Barlow & Reeves, 1979; S. E. Palmer & Hemenway, 1978; Royer, 1981). Four experiments were conducted to examine capacity limits in different symmetry judgments. Observers were required to discriminate between random patterns and approximate symmetry (Experiments 1 and 3) or between perfect and approximate symmetry (Experiments 2 and 4). The patterns were divided into two sets of dots, presented either simultaneously or successively. A comparison of accuracy under these two presentation conditions suggested that symmetry detection involves an analysis that is spatially parallel but coarse, regardless of either task difficulty or task type (detecting symmetry vs. detecting asymmetry).  相似文献   
97.
Senior capstone design and ethics: A bridge to the professional world   总被引:1,自引:1,他引:0  
A senior level capstone design experience has been developed and offered with a particular emphasis on many of the professional issues raised in Accreditation Board for Engineering and Technology (ABET) Engineering Criterion IV. The course has sought to develop student awareness of the ethical foundation of the engineering profession, the global and societal framework within which engineers practice, and the environmental impact on engineering. The capstone design course also focused upon improving the technical communications skills of the graduating senior class with both extensive instruction in writing and multiple workshops dealing with the art of making an effective oral presentation. The effectiveness of the design course was assessed using Kirkpatrick’s model for evaluating training programs. An earlier version of this paper was presented at the “Ethics and Social Responsibility in Engineering and Technology” meeting, New Orleans, 2003.  相似文献   
98.
Faculty members at Canadian business schools were surveyed regarding their ethical perceptions of behaviours related to undergraduate instruction. Fifty-five behavioural statements were listed and respondents were asked to rate the extent to which they felt each behaviour was ethical or unethical. The only item that respondents endorsed as unequivocally unethical (90% indicated it was definitely unethical) was Becoming sexually involved with an undergraduate in one of your classes. We also compared the results of our sample to those of an American sample. Overall, an interesting pattern of differences emerged between the responses obtained in Canada and the U.S. In general, the direction of the significant differences was such that Canadian professors viewed the behaviours in question as less ethical than did their American counterparts.  相似文献   
99.
Effects of experience on fetal voice recognition   总被引:1,自引:0,他引:1  
Abstract - The ability of human fetuses to recognize their own mother's voice was examined. Sixty term fetuses were assigned to one of two conditions during which they were exposed to a tape recording of their mother or a female stranger reading a passage. Voice stimuli were delivered through a loudspeaker held approximately 10 cm above the maternal abdomen and played at an average of 95 dB SPL. Each condition consisted of three 2-min periods: no stimulus, voice (mother or stranger), and no stimulus. Fetal heart rate increased in response to the mother's voice and decreased in response to the stranger's; both responses were sustained for 4 min. The finding of differential behavior in response to a familiar versus a novel voice provides evidence that experience influences fetal voice processing. It supports an epigenetic model of speech perception, presuming an interaction between genetic expression of neural development and species-specific experience.  相似文献   
100.
To study maternal question-asking of Taiwanese children during free play and at meal time each mother-child dyad was videotaped at home. The mothers of children with Down syndrome asked more questions across different types of question during free play, at meal time, and for the sum of these two. Although no group difference was found for producing each type of question during free play, these 20 mothers asked more directive questions at meal time. Combined conditions analysis showed they used more directive questions and fewer requests for clarification than the 20 mothers of children with no disability.  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