全文获取类型
收费全文 | 138篇 |
免费 | 5篇 |
专业分类
化学 | 53篇 |
力学 | 17篇 |
综合类 | 5篇 |
数学 | 50篇 |
物理学 | 18篇 |
出版年
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 7篇 |
2020年 | 5篇 |
2019年 | 10篇 |
2018年 | 7篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 12篇 |
2012年 | 6篇 |
2011年 | 3篇 |
2010年 | 2篇 |
2009年 | 4篇 |
2008年 | 5篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 6篇 |
2003年 | 6篇 |
2002年 | 2篇 |
1999年 | 2篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1988年 | 2篇 |
1986年 | 2篇 |
1979年 | 1篇 |
排序方式: 共有143条查询结果,搜索用时 234 毫秒
121.
创新是当今的时代精神.创新能力的培养是实施素质教育的重要目标之一.高等数学作为高等教育的重点基础课程,在训练和培养学生创新能力方面具有重要地位.如何在高等数学教学过程中培养学生的创新思维,提高创新能力是我们高等数学教学改革的重要任务.文章通过对当前教育形势的分析以及创新思维的特点的思考,从教学理念、教学模式以及教学内容三个方面讨论了在高等数学教学过程中学生的创新思维的培养问题. 相似文献
122.
Maria Kordaki Despina Potari 《International Journal of Computers for Mathematical Learning》2002,7(1):65-100
This study focuses on the role of tools, provided by a computer microworld (C.AR.ME), on the strategies developed by 14-year-old students for the area measurement of a non-convex polygon. Students' strategies on a transformation and a comparison task were interpreted and classified into categories in terms of the tools used for their development. The analysis of the data shows that an environment providing the students with the opportunity to select various tools and asking them to produce solutions `in any possible way' can stimulate them to construct a plurality of solution strategies. The students selected tools appropriate for their cognitive development and expressed their own individual approaches regarding the concept of area measurement. The nature of tools used affected the nature of solution strategies that the students constructed. Moreover, all students were involved in the tasks and succeeded in completing them with more than one correct solution strategy thereby developing a broader view of the concept, although not all of them realized the same strategies. Three different approaches to area measurement emerged from the strategies which were constructed by the students in this microworld: automatic area measurement, provided by the environment, the operation of area measurement using spatial units and the use of area formulae. Almost all the students experienced qualitative aspects of area measurement through being involved in the process of covering areas using spatial units. Students also managed to use the area formulae meaningfully by studying it in relation to automatic area measurement and to area measurement using spatial units. Through these strategies, the concepts of conservation of area and its measurement as well as area formulae were viewed by the students as interrelated. Finally, some basic difficulties regarding area measurement were overcome in this computer environment.This revised version was published online in September 2005 with corrections to the Cover Date. 相似文献
123.
In this paper the notion of robot-manipulators in the Euclidean space is generalized to the case in a general homogeneous
space with the Lie group G of motions. Some kinematic subspaces of the Lie algebra (the subspaces of velocity operators, of Coriolis acceleration operators, asymptotic subspaces) are ntroduced and by them
asymptotic and geodesic motions are described. 相似文献
124.
** Email: seligjm{at}lsbu.ac.uk The concept of curves of minimal acceleration seems to havebeen introduced by efran and Kumar and independently by Noakes,Heinzinger and Paden. In part, the motivation was to extendthe notion of spline curves to curves in groups, specificallythe groups associated with robotics. A curve in the rigid-bodymotion group SE(3), e.g. can be thought of as a trajectory ofa rigid body. Hence, these ideas have applications to motionplanning and interpolation. In this work, the analysis is repeatedbut using bi-invariant metrics on the group. Since these metricsare not positive definite, the curves specified by the equationsderived are only stationary, not minimal. It is possible tosolve these non-linear coupled differential equations in somesimple cases. However, these simple cases turn out to be highlyrelevant to robotics and mechanism theory. 相似文献
125.
126.
127.
针对在线教育中试题知识点自动标注问题,本文提出了一种基于二部图的试题知识点标注方法。首先,为了合理划分知识点粒度,本文构建了知识点知识图谱来融合知识点;其次,基于教材等语料抽取知识点与特征词二部图和试题与特征词二部图,并利用TF-IDF公式计算知识点与特征词、试题与特征词之间的边权,以构建试题-知识点二部图模型;再次,提出词频加权的相似性度量方法计算试题和知识点之间的相似度,将相似度最高的知识点作为试题知识点标签。最后,以某在线教育平台提供的高中历史试题为实验数据集进行数值实验,实验结果表明该方法的效果显著优于朴素贝叶斯、K最近邻、随机森林以及支持向量机。 相似文献
128.
129.
Abraham Seidmann 《Annals of Operations Research》1988,15(1):289-311
An optimal routing policy is obtained for Flexible Manufacturing Systems (FMSs) with limited buffers at the work stations. This policy is used to effectively drive a robotic material handling system. The routing decisions are made by a supervising computer on a real-time basis in order to avoid any work station running out of inputs and to control the blocking of the material handling system. Using our model, general material handling times can be assumed. The optimal policy and several key performance measures are computed, following the problem formulation as a continuous-time, semi-Markovian decision process. Fast convergence and computational stability are ensured by the ergodic solution algorithm augmented to solve the functional equations of the renewal process. The solution algorithm was implemented, tested on an extensive range of problems regarding the structure and the performance of the optimal policy. Complex environments involving diverse processing times, as well as very limited buffer storage, were examined. The interaction between the allocation of buffer spaces to work stations, the structural properties of the optimal monotone (threshold-type) policy and the system performance are also investigated. 相似文献
130.
通过对碳单质概念发展历程的考证可知,碳是古代已知的非金属元素。至17—18世纪,随着科学实验的兴起和元素观的发展,金刚石和石墨均被证明为碳的单质,碳单质概念初步形成;20世纪80年代C60的发现及之后碳纳米管、石墨烯和T-碳的发现使人们对碳单质概念有了新认识。在化学教育中,须让学生认识到碳单质概念的发展史是物质的发现史,也是科学思想的演进史和科学方法的发展史。 相似文献