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1.
基于用户信息需求的元搜索引擎的构建 总被引：5，自引：0，他引：5
针对当前网络搜索引擎未能较多地关注用户需求、查全率与查准率不高、彼此间不兼容的缺陷,提出建立基于用户需求的元搜索引擎,并分析其基本原理,给出其基本结构,讨论其运行机制和关键技术。指出基于用户需求的元搜索引擎可使网络信息资源在一定程度上结构化,实现网络信息资源的自组织,提高网络信息检索的查全率和查准率. 相似文献
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中文全文标引的主题词标引和主题概念标引方法1 总被引：20，自引：3，他引：17
中文全文标引正在越来越受到重视。本文主要研究了三个方面的问题，首先是全文主题词标引的加权问题，综合考虑了五个方面的因素；其次是介绍了一种用层次概念词典改进主题词标引质量的新方法；最后又提出了用三种不同的方法产生主题概念进行全文标引的的主题概念标引。受限范围内的实验结果显示本文的方法有一定的理论和实用价值。 相似文献
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Elena Lui Hah Wah 《Asia Pacific Journal of Education》1985,7(1):22-26
Stanley Coopersmith (1981. p. 5) defines self-esteem as “the evaluation a person makes and customarily maintains with regard to him- or herself. ‘Self-esteem’ expresses an attitude of approval or disapproval and indicates the extent to which a person believes him- or herself capable, significant, successful and worthy.” This judgement of worthiness of oneself is relatively enduring and general rather than transitory and specific. A person's self-esteem may vary across different areas of experience and role-defined conditions but one will presumably weigh these areas according to their subjective importance and then arrive at a general level of self-esteem. Attitude toward the “self” may or may not be noticed consciously. However, it can be detected through one's behaviour and performance. 相似文献
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一般来说,在语篇中前指词必须有先行词,两者在性数上应该保持一致。但在中国古典名著<红楼梦>中,我们发现了两个例外:其一,第三人称代词前指词在语篇中没有先行词;其二,前指词与其先行词在性和数上不一致。本文作者认为,这两种特殊情况只能从社会语言学角度来解释,因为它们是由交际者之间的人际关系所决定的。 相似文献
6.
Kyeong Hah Roh 《Educational Studies in Mathematics》2008,69(3):217-233
There are many studies on the role of images in understanding the concept of limit. However, relatively few studies have been
conducted on how students’ understanding of the rigorous definition of limit is influenced by the images of limit that the
students have constructed through their previous learning. This study explored how calculus students’ images of the limit
of a sequence influence their understanding of definitions of the limit of a sequence. In a series of task-based interviews,
students evaluated the propriety of statements describing the convergence of sequences through a specially designed hands-on
activity, called the ɛ–strip activity. This paper illustrates how these students’ understanding of definitions of the limit of a sequence was influenced
by their images of limits as asymptotes, cluster points, or true limit points. The implications of this study for teaching
and learning the concept of limit, as well as on research in mathematics education, are also discussed. 相似文献
7.
马福山 《连云港师范高等专科学校学报》2011,(4):81-84
加快经济发展方式转变是连云港市经济发展面临的重要课题。目前,连云港市经济发展方式存在结构不合理、新兴产业竞争力不强、民生改善投入不足等问题。文章分析了该市经济发展方式转变的有利和不利条件,并从更新观念、做好基础工作、培育新兴产业、创新驱动和教育领先等方面提出改进的具体策略。 相似文献
8.
Kyeong Hah Roh 《Educational Studies in Mathematics》2010,73(3):263-279
This study explored students’ understanding of a logical structure in defining the limit of a sequence, focusing on the relationship
between ε and N. The subjects of this study were college students who had already encountered the concept of limit but did not have any experience
with rigorous proofs using the ε–N definition. This study suggested two statements, each of which is written by using a relationship between ε and N, similar to the ε–N definition. By analyzing the students’ responses to the validity of the statements as definitions of the limit of a sequence,
students’ understanding of such a relationship was classified into five major categories. This paper discusses some essential
components that students must conceptualize in order properly to understand the relationship between ε and N in defining the limit of a sequence. 相似文献
9.
本文报道采自贵州的轮藻植物，计有4个新种(平滑丽藻Nitella rasilis sp．nov., 沼泽丽藻N．
paludosa sp．nov.，拟乳突丽藻N．pseudopapillata sp．nov． 贵州丽藻N．guizhouensis sp．nov．)；
1个新变种(奇异丽藻疏枝变种N．mirabilis var. libera var. nov.)；3个新记录(笔状丽藻N．peni-
cillata Braun缅甸轮藻Chara burmanica Pal，普生轮藻裸枝变种C．vulgaris var. gymnophylla (A．
Br.) Nyman)， 而拟松形轮藻 C. pseudohydropitys Imahori为大陆首次发现。 相似文献
10.
Yunnan is extends across the subtropical and tropical zones, situated in the sou-
thern border area of southwestern China. This district is extremely rich in plants, and
thus, it has been known as a “Kingdom of Plants”. However, up to the present our
knowledge of the Charophyta in this region has been scanty.
In order to get a thorough understanding of its Charophyta, we identified speci-
mens collected from 13 countries or cities in this province. The result shows that is
especially abundant in Charophyta.
In this paper, however, only are reported new species, new varieties and new re-
cords of China on the Nitelleae. The former two are Nitella hokouensis, N. bicornuta,
N. longicaudata, N. procera, N. brevidactyla, N. papillata, N. pseudohyalina, N. hyalina
var. aberrans and Tolypella yunnanensis; while the third is Nitella globulifera Pal andN. japonica T. F. Allen. 相似文献