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   190篇
  免费   8篇
  国内免费   10篇
  2023年   3篇
  2022年   1篇
  2021年   6篇
  2020年   5篇
  2019年   3篇
  2018年   5篇
  2017年   2篇
  2016年   5篇
  2015年   4篇
  2014年   5篇
  2013年   13篇
  2012年   1篇
  2011年   2篇
  2010年   1篇
  2009年   3篇
  2008年   14篇
  2007年   11篇
  2006年   9篇
  2005年   13篇
  2004年   11篇
  2003年   12篇
  2002年   7篇
  2001年   8篇
  2000年   9篇
  1999年   7篇
  1998年   8篇
  1997年   3篇
  1996年   8篇
  1995年   6篇
  1994年   3篇
  1993年   2篇
  1992年   1篇
  1990年   1篇
  1989年   1篇
  1988年   2篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1982年   1篇
  1981年   2篇
  1979年   1篇
  1978年   2篇
  1977年   2篇
  1976年   1篇
  1975年   1篇
排序方式: 共有208条查询结果,搜索用时 31 毫秒
151.
In this paper we show that the class of fork squares has a complete orthodox axiomatization in fork arrow logic (FAL). This result may be seen as an orthodox counterpart of Venema's non-orthodox axiomatization for the class of squares in arrow logic. FAL is the modal logic of fork algebras (FAs) just as arrow logic is the modal logic of relation algebras (RAs). FAs extend RAs by a binary fork operator and are axiomatized by adding three equations to RAs equational axiomatization. A proper FA is an algebra of relations where the fork is induced by an injective operation coding pair formation. In contrast to RAs, FAs are representable by proper ones and their equational theory has the expressive power of full first-order logic. A square semantics (the set of arrows is U×U for some set U) for arrow logic was defined by Y. Venema. Due to the negative results about the finite axiomatizability of representable RAs, Venema provided a non-orthodox finite axiomatization for arrow logic by adding a new rule governing the applications of a difference operator. We address here the question of extending the type of relational structures to define orthodox axiomatizations for the class of squares. Given the connections between this problem and the finitization problem addressed by I. Németi, we suspect that this cannot be done by using only logical operations. The modal version of the FA equations provides an orthodox axiomatization for FAL which is complete in view of the representability of FAs. Here we review this result and carry it further to prove that this orthodox axiomatization for FAL also axiomatizes the class of fork squares.  相似文献   
152.
Marx  Maarten 《Studia Logica》2002,72(2):233-252
The complexity of the satisfiability problems of various arrow logics and cylindric modal logics is determined. As is well known, relativising these logics makes them decidable. There are several parameters that can be set in such a relativisation. We focus on the following three: the number of variables involved, the similarity type and the kind of relativised models considered. The complexity analysis shows the importance and relevance of these parameters.  相似文献   
153.
Multiple‐choice tests are frequently used in personnel selection contexts to measure knowledge and abilities. Option weighting is an alternative multiple‐choice scoring procedure that awards partial credit for incomplete knowledge reflected in applicants’ distractor choices. We investigated whether option weights should be based on expert judgment or on empirical data when trying to outperform conventional number‐right scoring in terms of reliability and validity. To obtain generalizable results, we used repeated random sub‐sampling validation and found that empirical option weighting, but not expert option weighting, increased the reliability of a knowledge test. Neither option weighting procedure improved test validity. We recommend to improve the reliability of existing ability and knowledge tests used for personnel selection by computing and publishing empirical option weights.  相似文献   
154.
Fuzzy logics are in most cases based on an ad-hoc decision about the interpretation of the conjunction. If they are useful or not can typically be found out only by testing them with example data. Why we should use a specific fuzzy logic can in general not be made plausible. Since the difficulties arise from the use of additional, unmotivated structure with which the set of truth values is endowed, the only way to base fuzzy logics on firm ground is the development of alternative semantics to all of whose components we can associate a meaning. In this paper, we present one possible approach to justify ex post Łukasiewicz Logic as well as Basic Logic. The notion of ambiguity is central. Our framework consists of a Boolean or a Heyting algebra, respectively, endowed with an equivalence relation expressing ambiguity. The quotient set bears naturally the structure of an MV- or a BL-algebra, respectively, and thus can be used to interpret propositions of the mentioned logics.  相似文献   
155.
156.
以初中代数应用题为材料,探讨了不同年级学生对代数应用题的分类结果与数学成绩的关系。结果表明:不同年级学生对代数应用题分类结果差异显著;数学成绩优生与数学成绩差生对代数应用题分类结果差异显著。  相似文献   
157.
Rasch analysis is a popular statistical tool for developing and validating instruments that aim to measure human performance, attitudes and perceptions. Despite the availability of various software packages, constructing a good instrument based on Rasch analysis is still considered to be a complex, labour-intensive task, requiring human expertise and rather subjective judgements along the way. In this paper we propose a semi-automated method for Rasch analysis based on first principles that reduces the need for human input. To this end, we introduce a novel criterion, called in-plus-out-of-questionnaire log likelihood (IPOQ-LL). On artificial data sets, we confirm that optimization of IPOQ-LL leads to the desired behaviour in the case of multi-dimensional and inhomogeneous surveys. On three publicly available real-world data sets, our method leads to instruments that are, for all practical purposes, indistinguishable from those obtained by Rasch analysis experts through a manual procedure.  相似文献   
158.
Although findings from cognitive science have suggested learning benefits of confronting errors (Metcalfe, 2017), they are not often capitalized on in many mathematics classrooms (Tulis, 2013). The current study assessed the effects of examples focused on either common mathematical misconceptions and errors or correct concepts and procedures on algebraic feature knowledge and solving quadratic equations. Middle school algebra students (N = 206) were randomly assigned to four conditions. Two errorful conditions either displayed errors and asked students to explain or displayed correct solutions and primed students to reflect on potential errors by problem type. A correct example condition and problem-solving control group were also included. Studying and explaining common errors displayed in incorrect examples improved equation-solving ability. An aptitude-by-treatment interaction revealed that learners with limited understandings of algebraic features demonstrated greater benefits. Theoretical implications about using examples to promote learning from errors are considered in addition to suggestions for educational practice.  相似文献   
159.
Gaitán  Hernando 《Studia Logica》2000,64(1):83-92
In this paper we describe the Priestley space of a quasi-Stone algebra and use it to show that the class of finite quasi-Stone algebras has the amalgamation property. We also describe the Priestley space of the free quasi-Stone algebra over a finite set. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   
160.
The ELECTRE family of decision aid methods is a well‐known approach to help decision makers (DMs) advance in a decision process. Among the most recent methods in the family, ELECTRE IS, III, and TRI compute fuzzy indices for the credibility of a given action outranking some other. We consider the case when the DMs are unsure which values each parameter should take, which may result from insufficient, imprecise or contradictory information, as well as from different preferences among a group of DMs. In the framework of a robustness analysis approach, where DMs provide only partial information on the parameter values (through constraints on acceptable combinations), we study how to find whether an outranking among two actions in an ELECTRE method is robust. In this context, we study the resulting nonlinear problems of optimizing a credibility index (under the type of constraints that we consider to appear in practice) and present some examples. Copyright © 1999 John Wiley & Sons, Ltd.  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