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   2707篇
  免费   242篇
  国内免费   311篇
  3260篇
  2024年   10篇
  2023年   51篇
  2022年   51篇
  2021年   93篇
  2020年   155篇
  2019年   148篇
  2018年   160篇
  2017年   148篇
  2016年   154篇
  2015年   120篇
  2014年   133篇
  2013年   418篇
  2012年   88篇
  2011年   127篇
  2010年   75篇
  2009年   118篇
  2008年   113篇
  2007年   123篇
  2006年   108篇
  2005年   107篇
  2004年   112篇
  2003年   94篇
  2002年   74篇
  2001年   61篇
  2000年   60篇
  1999年   39篇
  1998年   35篇
  1997年   32篇
  1996年   23篇
  1995年   37篇
  1994年   22篇
  1993年   8篇
  1992年   11篇
  1991年   12篇
  1990年   8篇
  1989年   12篇
  1988年   9篇
  1987年   11篇
  1986年   6篇
  1985年   9篇
  1984年   15篇
  1983年   8篇
  1982年   13篇
  1981年   8篇
  1980年   7篇
  1979年   12篇
  1977年   4篇
  1976年   3篇
  1975年   7篇
  1974年   4篇
排序方式: 共有3260条查询结果,搜索用时 0 毫秒
231.
Most Chinese characters are composed of a semantic radical on the left and a phonetic radical on the right. The semantic radical provides the semantic information; the phonetic radical provides information concerning the pronunciation of the whole character. The pseudo‐characters in the study consisted of different sub‐lexical parts of real Chinese characters and consequently they also had the semantic radical and the phonetic radical. But they were not readable and had no actual meaning. In order to investigate the spatiotemporal cortical activation patterns underlying the orthographic, phonological and semantic processing of Chinese characters, we used event‐related brain potentials (ERPs) to explore the processing of Chinese characters and pseudo‐characters when 14 healthy Chinese college students viewed the characters passively. Results showed that both Chinese characters and pseudo‐characters elicited an evident negative potential peaking around 120 ms (N120), which appeared to reflect initial orthographic distinction and evaluation. Then, Chinese pseudo‐characters elicited a more positive ERP deflection (P220) than did Chinese characters 200–250 ms after onset of the stimuli. It was similar to the recognition potential (RP) and might reflect the integration processes of phonological and semantic processing on the basis of early orthographic information. Dipole source analysis of the difference wave (pseudo‐characters minus characters) indicated that a generator localized in the left temporal‐occipital junction contributed to this effect, which was possibly related to phonological and perceptual–semantic information integration. Between 350–450 ms, a greater negativity (N360) in pseudo‐characters as compared to characters was found over midline fronto‐central scalp regions. Dipole analysis localized the generator of N360 in the right parahippocampal cortex. Therefore, the N360 might be an N400 component and reflect the higher‐level semantic activation on the basis of orthographic, phonological and perceptual–semantic processing.  相似文献   
232.
233.
Adaptive learning games should provide opportunities for the student to learn as well as motivate playing until goals have been reached. In this paper, we give a mathematically rigorous treatment of the problem in the framework of Bayesian decision theory. To quantify the opportunities for learning, we assume that the learning tasks that yield the most information about the current skills of the student, while being desirable for measurement in their own right, would also be among those that are efficient for learning. Indeed, optimization of the expected information gain appears to naturally avoid tasks that are exceedingly demanding or exceedingly easy as their results are predictable and thus uninformative. Still, tasks that are efficient for learning may be experienced as too challenging, and the resulting failures can lower motivation. Therefore, in addition to quantifying the expected informational benefit for learning of any prospective task to be presented next, we also model the expected motivational cost of its presentation, measured simply as the estimated probability of failure in our example model. We propose a “learner-friendly” adaptation algorithm that chooses the learning tasks by optimizing the expected benefit divided by the expected cost. We apply this algorithm to a Rasch-like student model implemented within a real-world application and present initial results of a pilot experiment.  相似文献   
234.
Since the 1930s it has been widely acknowledged that agricultural crop diversity is being lost at an alarming rate. The international response to this genetic erosion has principally taken the form of ex situ genebanks. In these facilities and in the international regulatory frameworks that now surround them, it is genetic diversity that is the focus of conservation efforts. This focus, however, passes over the many other important diversities—both biological and social (or ‘biosocial’)—that exist in, and depend on, agricultural environments. These diversities cannot be conserved in genebanks. In addition to failing to actually conserve agricultural diversity (in any full sense of the term), ex situ banking projects also produce important potential inequalities—in terms of which material is banked and who has access to it. If, however, we refuse to accept an exclusive focus on the genetic components of plants, and instead insist on a brand of conservation that includes whole biosocial, more-than-human communities, then the role of banked resources must be radically rethought. Genebanks might instead take the place of central nodes in networks of diversity sharing, helping to keep plant varieties growing and circulating. This focus, in turn, requires that we also pay more critical attention to the various economic, legal and other mechanisms that prevent or stifle the flow and development of plant genetic resources in/to agricultural communities—especially those of peasant and indigenous farmers that play such a crucial role in conserving the world's (agro)biodiversity.  相似文献   
235.
Nowadays, the criticism of the so-called ‘deficit model’ and the need for ‘upstream engagement’ in science and technology are becoming part of the master narratives of public policies in many countries, especially concerning nanotechnology. This may be considered as a major success for STS scholars, whose research results have largely contributed to this change, especially those concerning the GMO controversies. Some STS scholars thus move from a position of distant and critical observers to the role of experts in social engineering or advisers of policy-makers. However, in their enthusiasm concerning the expected benefits of upstream engagement, institutions, TA practitioners and social scientists seem to ignore some important limitations as well as the implicit framing assumptions of the concept. Based on an experience made by a group of social scientists in the Grenoble area—one of the major ‘nanodistricts’ in Europe—our paper shows that the ‘upstream engagement’ concept is still embedded in a linear model of innovation and is not very useful to anyone pursuing the co-production of innovations. It is especially true when socio-technical networks are already aligned by powerful actors and a worldwide agenda as in the case of nanotechnology. In order to give an opportunity for public engagement to have a larger impact on decision-making, we propose an alternative approach, which combines Actor–Network Theory (ANT), as an analytical tool, with the reflexive and ongoing implementation of public participation. Public engagement is probably one of the critical loci where STS scholars must reflect on the articulation between the knowledge they produce and public policies in action.  相似文献   
236.
ABSTRACT

To some extent, the early twentieth century revival of universal languages was the work of logicians and mathematicians. Pioneers of modern logic such as Frege, Russell and Peano wanted to overcome the diversity and deficiencies of natural languages. Through the rigour of formal logic, they aimed at providing scientific thinking with a reliable medium free from the ambiguity and inconsistencies of ordinary language. This article shows some interconnections between modern logic and the search for a common tongue that would unite scientists and people of all nations. The French mathematician and philosopher Louis Couturat is a key figure in understanding the interplay between these two movements. Through his work in composing the Ido language as an alternative to Esperanto, Couturat gave a new life to the Leibnizian idea of a universal characteristics. In addition, his multifaceted work provides a valuable insight into some political implications of early analytic philosophy.  相似文献   
237.
We offer a social psychological perspective on gender-related inequalities in close relationships and integrate two lines of research that have focused on the intrapersonal perceptions and interpersonal consequences respectively of the gendered division of labour. We start with a brief summary of research on gender-related inequalities in the division of labour and discuss prior explanations and paradigms. We then address the extent to which spouses consider the division of labour as fair and the factors that contribute to perceptions of (un)fairness. Central to our argument is the distributive justice framework (<citeref rid="b76">Major, 1987</citeref>, <citeref rid="b77">1993</citeref>; <citeref rid="b113">Thompson, 1991</citeref>) which claims that fairness judgements are affected by people's wants and values, comparison standards, and justifications. In the following section, we address the question of whether dissatisfaction over the division of labour causes relationship conflict and how couples manage these conflicts. The main argument is that conflict over the division of labour generally comprises an asymmetrical conflict structure (with wives as complainants and husbands as defenders of the status quo), which elicits asymmetrical conflict interaction patterns (i.e., demand/withdraw interaction) that result in asymmetrical outcomes (i.e., status quo maintenance). Finally, we summarise the main conclusions and address contributions to theory and research as well as directions for further research.  相似文献   
238.
No abstract available for this article.  相似文献   
239.
This study aimed to explore Chinese children's social value orientation across different ages and contexts. Revised decomposed games were used to measure the social value orientation of 9‐, 11‐, and 14‐year‐old children and college students as an adult group. About half of them were assigned to the hypothetical context of “equal payment group,” providing equal compensation for participation in the study, and the others to the “real payment group,” who got payment according to their own choices in the games. Results showed that 9‐ and 11‐year‐old children's choices differed between the two contexts: They made more prosocial choices in the hypothetical context, and more competitive choices in the “real payment” context. The 14‐year‐olds’ and adults’ choices were not significantly different in the two contexts. These results may imply that by 14 years of age, children have stable social value orientation, and their behavior reflects this value.  相似文献   
240.
This study aimed to investigate the mechanisms underlying joke comprehension using event‐related potentials (ERPs). Fourteen healthy college students were presented with the context of a story without its joke or nonjoke ending, and then, when the story ending was presented, they were asked to make a funny/unfunny judgment about these endings. The behavioral results showed that there was no significant difference between funny and unfunny items, which meant that subjects could understand funny items as easily as unfunny ones. However, the ERP results showed that funny items initially elicited a more negative ERP deflection (N350–450) over frontocentral scalp regions. Dipole analysis localized the generators in the left temporal gyrus and the left medial frontal gyrus; it is suggested that these areas might be involved in detecting the incongruent element in joke comprehension. Between 600 and 800 ms, funny items subsequently elicited a more negative ERP deflection (N600–800) over frontocentral scalp regions and a more positive ERP deflection (P600–800) over posterior scalp regions. Dipole analysis localized the generator in the anterior cingulate cortex (ACC), an area involved in the breaking of mental set/expectation and the forming of novel associations. Finally, funny items elicited a more positive ERP deflection (P1250–1400) over anterior and posterior scalp regions. Dipole analysis localized the generators in the middle frontal gyrus and the fusiform gyrus, areas that might be related to the affective appreciation stage in joke process. Unlike that of Coulson and Kutas (2001), the present study might support the hypothesis of a three stage model of humor processing (humor detection, resolution of incongruity and humor appreciation).  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