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   1045篇
  免费   7篇
教育   748篇
科学研究   69篇
各国文化   10篇
体育   95篇
文化理论   4篇
信息传播   126篇
  2023年   3篇
  2022年   6篇
  2021年   12篇
  2020年   18篇
  2019年   28篇
  2018年   39篇
  2017年   42篇
  2016年   58篇
  2015年   18篇
  2014年   40篇
  2013年   239篇
  2012年   27篇
  2011年   33篇
  2010年   25篇
  2009年   39篇
  2008年   39篇
  2007年   30篇
  2006年   31篇
  2005年   33篇
  2004年   16篇
  2003年   16篇
  2002年   21篇
  2001年   16篇
  2000年   14篇
  1999年   18篇
  1998年   10篇
  1997年   14篇
  1996年   8篇
  1995年   9篇
  1994年   6篇
  1993年   14篇
  1992年   7篇
  1991年   4篇
  1990年   8篇
  1989年   13篇
  1988年   6篇
  1987年   5篇
  1986年   7篇
  1985年   13篇
  1984年   6篇
  1983年   8篇
  1982年   8篇
  1981年   5篇
  1980年   4篇
  1978年   4篇
  1973年   3篇
  1940年   2篇
  1928年   2篇
  1923年   3篇
  1919年   2篇
排序方式: 共有1052条查询结果,搜索用时 15 毫秒
971.
The cost effectiveness and quality of full-text journals are analyzed for four prominent online aggregated journal packages: EBSCOhost Academic Search FullTEXT, UMI Proquest Direct Periodicals Research II, IAC’s Expanded Academic ASAP, and H.W. Wilson’s OmniFile. Price data from EBSCO’s Librarians’ Handbook are used to assess the total and average value of social sciences journals in each package. Quality of social sciences journals coverage is compared based on citation impact factors as recorded in Journal Citation Reports—Social Sciences Edition.  相似文献   
972.
The advent of formal definitions of the simplicity of a theoryhas important implications for model selection. But what isthe best way to define simplicity? Forster and Sober ([1994])advocate the use of Akaike's Information Criterion (AIC), anon-Bayesian formalisation of the notion of simplicity. Thisforms an important part of their wider attack on Bayesianismin the philosophy of science. We defend a Bayesian alternative:the simplicity of a theory is to be characterised in terms ofWallace's Minimum Message Length (MML). We show that AIC isinadequate for many statistical problems where MML performswell. Whereas MML is always defined, AIC can be undefined. WhereasMML is not known ever to be statistically inconsistent, AICcan be. Even when defined and consistent, AIC performs worsethan MML on small sample sizes. MML is statistically invariantunder 1-to-1 re-parametrisation, thus avoiding a common criticismof Bayesian approaches. We also show that MML provides answersto many of Forster's objections to Bayesianism. Hence an importantpart of the attack on Bayesianism fails.
  1. Introduction
  2. TheCurve Fitting Problem
    2.1 Curves and families of curves
    2.2 Noise
    2.3 Themethod of Maximum Likelihood
    2.4 ML and over-fitting
  3. Akaike's Information Criterion(AIC)
  4. The Predictive Accuracy Framework
  5. The Minimum MessageLength (MML) Principle
    5.1 The Strict MML estimator
    5.2 Anexample: Thebinomial distribution
    5.3 Properties ofthe SMML estimator
    5.3.1  Bayesianism
    5.3.2  Languageinvariance
    5.3.3Generality
    5.3.4  Consistencyand efficiency
    5.4 Similarity to false oracles
    5.5 Approximationsto SMML
  6. Criticisms of AIC
    6.1 Problems with ML
    6.1.1  Smallsample biasin a Gaussian distribution
    6.1.2  Thevon Misescircular and von Mises—Fisherspherical distributions
    6.1.3  The Neyman–Scottproblem
    6.1.4  Neyman–Scott,predictive accuracyandminimum expected KL distance
    6.2 Otherproblems with AIC
    6.2.1  Univariate polynomial regression
    6.2.2  Autoregressiveeconometric time series
    6.2.3  Multivariatesecond-orderpolynomial modelselection
    6.2.4  Gapor no gap:a clustering-like problem forAIC
    6.3 Conclusionsfrom the comparison of MML and AIC
  7. Meeting Forster's objectionsto Bayesianism
    7.1 The sub-family problem
    7.2 Theproblem of approximation,or, which framework forstatistics?
  8. Conclusion
  1. Details of the derivation of the Strict MMLestimator
  2. MML, AIC and the Gap vs. No Gap Problem
    B.1 Expectedsize of the largest gap
    B.2 Performanceof AIC on thegap vs. no gap problem
    B.3 Performanceof MML in thegap vs. no gap problem
  相似文献   
973.
The use of instructional videos to teach clinical skills is an ever growing area of e‐learning based upon observational learning that is cited as one of the most basic yet powerful learning strategies. The aim of the current study is to evaluate the effectiveness of online instructional videos for the acquisition and demonstration of cognitive, affective and psychomotor skills among undergraduate students, throughout formative assessments with two different durations of instructional videos. The research suggests that the use of videos to support traditional learning should be encouraged. While a conclusive evidence—base for their usage has not yet been established they are a medium which is likely to benefit a proportion of a cohort, and it is very unlikely that they will be harmful to students' learning.  相似文献   
974.
975.
976.
In America the ethic of individual achievement has always been balanced by complementary norms of group action. Blacks, however, have been handicapped by a lack of the in-group loyalty required for a united struggle against racial oppression. Black power ideology was conceived as a sociotherapy to increase the level of black group cohesion. This study was designed to provide much needed data on the success of the “therapy.” A survey of 611 black high school students and 93 black college students yielded little evidence that verbally professed endorsement of black power ideology was translated into action. In an experiment. 323 black high school students manifested a consistent tendency to be less helpful to scientists identified as black than to unidentified scientists, regardless of the students' claimed level of black power orientation.  相似文献   
977.
978.
979.
980.
Considers the indexing of scientific and medical periodicals, covering the need for indexes, the effect on information retrieval of the electronic revolution, types of journals and entries, the process of indexing, cumulation, and publisherAndexer relations  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