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   2807篇
  免费   102篇
  国内免费   3篇
教育   1985篇
科学研究   191篇
各国文化   71篇
体育   338篇
综合类   2篇
文化理论   35篇
信息传播   290篇
  2023年   15篇
  2022年   29篇
  2021年   38篇
  2020年   91篇
  2019年   130篇
  2018年   150篇
  2017年   142篇
  2016年   171篇
  2015年   110篇
  2014年   123篇
  2013年   585篇
  2012年   81篇
  2011年   94篇
  2010年   64篇
  2009年   68篇
  2008年   81篇
  2007年   60篇
  2006年   55篇
  2005年   41篇
  2004年   42篇
  2003年   56篇
  2002年   30篇
  2001年   40篇
  2000年   24篇
  1999年   32篇
  1998年   28篇
  1997年   18篇
  1996年   23篇
  1995年   21篇
  1994年   28篇
  1993年   19篇
  1992年   27篇
  1991年   30篇
  1990年   23篇
  1989年   21篇
  1988年   23篇
  1987年   13篇
  1986年   17篇
  1985年   21篇
  1984年   21篇
  1983年   15篇
  1982年   9篇
  1981年   20篇
  1980年   12篇
  1979年   14篇
  1978年   28篇
  1977年   11篇
  1976年   11篇
  1974年   16篇
  1969年   9篇
排序方式: 共有2912条查询结果,搜索用时 31 毫秒
1.
Seventy-nine 3-year olds and their mothers participated in a laboratory-based task to assess maternal hostility. Mothers also reported their behavioral regulation of their child. Seven years later, functional magnetic resonance imaging data were acquired while viewing emotional faces and completing a reward processing task. Maternal hostility predicted more negative amygdala connectivity during exposure to sad relative to neutral faces with frontal and parietal regions as well as more negative left ventral striatal connectivity during monetary gain relative to loss feedback with the right posterior orbital frontal cortex and right inferior frontal gyrus. In contrast, maternal regulation predicted enhanced cingulo-frontal connectivity during monetary gain relative to loss feedback. Results suggest parenting is associated with alterations in emotion and reward processing circuitry 7–8 years later.  相似文献   
2.
The goal of the Standards for Educational and Psychological Testing is to improve testing practices, but their impact on practice appears spotty. Self-regulation clearly fails in some instances. The establishment of an external agency to oversee testing practices and adherence to the Standards would face substantial hurdles, and the ambiguity of many of the Standards would hobble such an organization if one were created. Many of the Standards are general statements of principle, and past controversies make clear that we in the field often disagree about the reasons for them, their applicability to specific cases, and their practical meaning in specific contexts. This paper argues that the field should follow two approaches to lessen this ambiguity. First, using journals, conferences, and other vehicles, we should foster more frequent and more protracted debate about the practical meaning of key Standards, such as 13.6 and 13.7, which mandate that a decision that will have a "major impact" on a student should not be based on a single score. Second, future revisions of the Standards should use concrete examples of testing practices to clarify the meaning of the Standards, much as the legal system uses case law to clarify the meaning of the general principles embodied in statutes .  相似文献   
3.
The paper deals with studies of engineering programmes in foreign languages at Vilnius Technical University (VTU), Lithuania. In order to organize studies in foreign languages, an International Studies Centre was established in 1992. The following aims were pursued: integrating into the systems of university education of European countries and promoting international exchange of students and staff. BSc studies (architecture, civil engineering, mechanical engineering and electronic engineering programmes) are organized in English, French and German. Over 150 undergraduate students from Lithuania and foreign countries are studying at the centre. About 150 students are enrolled for the next academic year.  相似文献   
4.
5.
6.
Book reviews     
cAbd al‐Malik b. Habib. Kitāb al‐Ta'rij (La historia). Edición y estudio por Jorge Aguadé. Madrid: Consejo Superior de Investigaciones Científicas & Instituto de Cooperación con el Mundo Arabe, 1991 (Fuentes Arabico‐Hispanas, 1). 163 + 224 pp. [Arabic title: Kltāb al‐Ta'tikh]

Kedar, Benjamin Z., ed. The Horns of Hattin. Jerusalem and London: Yad Izhak Ben‐Zvi, Israel Exploration Society and Variorum 1992. 368 pp., 12 plates; $74.75 (cloth).

Köprülü, Mehmed Fuad. The Seljuks of Anatolia: Their History and Culture According to Local Muslim Sources. Translated and edited by Gary Leiser. Salt Lake City: University of Utah, 1992. xi +101 pp., $22.00 (cloth).

Cameron, Averil and Conrad, Lawrence I., eds. The Byzantine and Early Islamic Near East: Problems in the Literary Source Material (Papers in the First Workshop on Late Antiquity and Early Islam). Princeton: The Darwin Press, 1992. xiv + 428pp., 12 plates; $29.25 (cloth).

Vereno, Ingolf. Studien zum ältesten alchemistischen Schrifttum. Berlin: Klaus Schwarz Verlag, 1992 (Islamkundliche Untersuchungen, 155). 414pp.

Tolan, John. Petrus Alfonsi and his Medieval Readers. Gainesville, Florida: University Press of Florida, 1993. xv + 288pp., $34.95 (cloth), $16.95 (paper).

Lassner, Jacob. Demonizing the Queen of Sheba: Boundaries of Gender and Culture in Postbiblical Judaism and Medieval Islam. Chicago: University of Chicago, 1994. 281 pp., $19.95 (paper), $49.95 (cloth).

Menocal, María Rosa. Shards of Love: Exile and the Origins of the Lyric. Durham, North Carolina: Duke University Press, 1994. xv + 295pp., $34.95 (cloth), $14.95 (paper).

Massignon, Louis. The Passion of al‐Hallāj, Mystic and Martyr of Islam. Translated and edited by Herbert Mason. Abridged edition, Bollingen Series XCVIII. Princeton: Princeton University Press, 1994. xxxi + 293pp.

Viguera Molins, Maria Jesús. El Islam en Aragón. Saragossa: Caja de Ahorros de la Inmaculada, 1995 (Colección “Mariano de Pano y Ruata”, 9), 174 pp., 182 ills. in colour, maps, diagrams, charts etc No price stated.  相似文献   

7.
With the plethora of health sites on the Internet, it is sometimes hard to know where to start. This is a basic list of health sites that either cover a subject area comprehensively, or are good general sites to lead to more specific information. Most of these sites include both full-text information as well as links to many other sites on the World-Wide Web. Included are medical, nursing, dental, alternative health, consumer health, organization, and government sites.  相似文献   
8.
Millions of Canadians residing in Canada's northern, isolated, rural, and remote communities do not have broadband Internet access. This situation has led to a national “broadband divide.” That is, the deployment of wireline broadband is very limited in Canada's northern, isolated, rural, and remote areas because of the significant expense of installation and maintenance of the wired infrastructure needed to reach dwellings in these locations.Terrestrial broadband wireless technology, on the other hand, does not entail the same kind of physical infrastructure. As a result, there are dramatic changes in how spatial considerations affect the provision of broadband Internet services (BIS) to areas beyond the urban zone. In particular, the spatial question is now focused on assessing the capacity for different technological solutions to reach profitable population bases, and brings to the forefront organizations that are developing non-line-of-sight (NLOS) technologies that would permit wireless Internet access over much greater distances than current solutions.We begin this paper by establishing the importance of broadband connectivity to Canada's northern, isolated, rural, and remote communities. This discussion comments on the role of the Government of Canada in the provision of broadband connectivity to residents of these communities, and outlines the current regulatory issues that govern wireless services and policy formulation.The second part of the paper illustrates the use of geographic information system (GIS) approaches in the study of wireless broadband planning and deployment. Case study findings suggest that GIS applications can make a significant contribution to the analysis of wireless deployment planning, to the understanding of the relationships between wireless signal sources and consumers, and to the spatial configuration of terrestrial wireless broadband networks. We conclude the paper by discussing how the GIS approach employed could be used to inform the public policy process with regard to increasing access to broadband Internet services in all regions of the country, and thereby providing the opportunity for all Canadians, regardless of location, to fully participate in the Information Society.  相似文献   
9.
Scale and Translation Invariant Collaborative Filtering Systems   总被引:1,自引:0,他引:1  
Collaborative filtering systems are prediction algorithms over sparse data sets of user preferences. We modify a wide range of state-of-the-art collaborative filtering systems to make them scale and translation invariant and generally improve their accuracy without increasing their computational cost. Using the EachMovie and the Jester data sets, we show that learning-free constant time scale and translation invariant schemes outperforms other learning-free constant time schemes by at least 3% and perform as well as expensive memory-based schemes (within 4%). Over the Jester data set, we show that a scale and translation invariant Eigentaste algorithm outperforms Eigentaste 2.0 by 20%. These results suggest that scale and translation invariance is a desirable property.  相似文献   
10.
Previous studies have shown that weeding a library collection benefits patrons and increases circulation rates. However, the time required to review the collection and make weeding decisions presents a formidable obstacle. This study empirically evaluated methods for automatically classifying weeding candidates. A data set containing 80,346 items from a large-scale weeding project running from 2011 to 2014 at Wesleyan University was used to train six machine learning classifiers to predict a weeding decision of either ‘Keep’ or ‘Weed’ for each candidate. The study found statistically significant agreement (p?=?0.001) between classifier predictions and librarian judgments for all classifier types. The naive Bayes and linear support vector machine classifiers had the highest recall (fraction of items weeded by librarians that were identified by the algorithm), while the k-nearest-neighbor classifier had the highest precision (fraction of recommended candidates that librarians had chosen to weed). The variables found to be most relevant were: librarian and faculty votes for retention, item age, and the presence of copies in other libraries.  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