共查询到19条相似文献，搜索用时 171 毫秒
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以甘肃省农业科学院订购的CNKI数据资源为例,根据数据商的在线统计数据,分析了2015 — 2017年CNKI数据库使用情况。甘肃省农业科学院的用户对CNKI期刊数据库浏览量和下载量较其他数据库高出很多,期刊全文下载以核心期刊和一级期刊为主,硕士论文下载量大于博士论文下载量。 相似文献
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《农业工程学报》2002,(4)
《中国科技期刊引证报告》( CJCR)及其本刊检索数据《中国科技期刊引证报告》( CJCR)是由中国科技信息研究所 ,选择多种期刊评价指标 ,以一定的中国科技论文统计源期刊 ( 2 0 0 0年为 1 40 6种期刊 )引用的数据为依据 ,对科技期刊论文进行统计分析 ,进而按照客观数据对期刊进行评价排序。该报告每年一版 ,为中国广大科技工作者 ,期刊编辑部和科研管理部门科学评价期刊 ,客观准确地选择和利用期刊提供了权威参考依据。统计数据表明 (见表 1 ) ,本刊最近 3年的影响在逐步扩大。统计数据表明 :本刊在农业工程类期刊中位居榜首 ,与农业类名… 相似文献
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严格把好图书分编质量关，提高用户检索效率，是图书馆编目部门应尽的责任，该文结合本人的工作实际，提出了加强图书馆书目数据质量控制的几点见解。 相似文献
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《中国生态农业学报》2011,(2)
《中国生态农业学报》原名《生态农业研究》,1993年创刊,中国科学院遗传与发育生物学研究所和中国生态经济学会主办,科学出版社出版。系中文核心期刊、中国期刊方阵双效期刊、中国科技核心期刊,中国科技论文统计源刊、万方数据库统计源刊、中国科学引文数据库源刊、中国期刊网统计源刊以及中国期刊全文数据 相似文献
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《中国生态农业学报》2011,(3)
《中国生态农业学报》原名《生态农业研究》,1993年创刊,中国科学院遗传与发育生物学研究所和中国生态经济学会主办,科学出版社出版。系中文核心期刊、中国期刊方阵双效期刊、中国科技核心期刊,中国科技论文统计源刊、万方数据库统计源刊、中国科学引文数据库源刊、中国期刊网统计源刊以及中国期刊全文数据 相似文献
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《中国生态农业学报》2010,(2)
<正>《中国生态农业学报》原名《生态农业研究》,1993年创刊,中国科学院遗传与发育生物学研究所和中国生态经济学会主办,科学出版社出版。系中文核心期刊、中国期刊方阵双效期刊、中国科技核心期刊,中国科技论文统计源刊、万方数据库统计源刊、中国科学引文数据库源刊、中国期刊网统计源刊以及中国期刊全文数据 相似文献
7.
《中国生态农业学报》2010,(1)
<正>《中国生态农业学报》原名《生态农业研究》,1993年创刊,中国科学院遗传与发育生物学研究所和中国生态经济学会主办,科学出版社出版。系中文核心期刊、中国期刊方阵双效期刊、中国科技核心期刊,中国科技论文统计源刊、万方数据库统计源刊、中国科学引文数据库源刊、中国期刊网统计源刊以及中国期刊全文数据 相似文献
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《中国生态农业学报》2010,(6)
<正>《中国生态农业学报》原名《生态农业研究》,1993年创刊,中国科学院遗传与发育生物学研究所和中国生态经济学会主办,科学出版社出版。系中文核心期刊、中国期刊方阵双效期刊、中国科技核心期刊,中国科技论文统计源刊、万方数据库统计源刊、中国科学引文数据库源刊、中国期刊网统计源刊以及中国期刊全文数据 相似文献
9.
中文期刊复杂、多变，笔者在总结期刊著录经验的基础上，就中文更名期刊这一特殊现象做简要分析。提出了从著录方法的选择、不同类型更名期刊的著录操作到后期数据维护一整套MARC著录方案。 相似文献
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Lutishoor Salisbury Jozef Laincz Jeremy J. Smith 《Journal Of Agricultural & Food Information》2013,14(3):250-266
This study compares undergraduate and graduate students’ preferences for information sources. It found that the largest percentage of undergraduates ranked Google Scholar, a scholarly database, as their 1st or 2nd choice for an information source, followed by Google, library scholarly databases, the library catalog, and library staff. The largest percentage of graduate students ranked library scholarly databases as their 1st or 2nd preference, followed by Google Scholar, the library catalog, Google, and library staff. There seems to be a connection between attendance in a library instruction session and the choice of library scholarly online databases. 相似文献
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在分析数据仓库和数据挖掘重要性的基础上,指出了数据挖掘的基本过程、数据挖掘的分类和应用,介绍了使用分类模型进行数据挖掘的应用实例,论述了实现原始数据到应用数据转换的方法。 相似文献
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《Journal Of Agricultural & Food Information》2013,14(3):33-50
ABSTRACT AGRICOLA is a widely used bibliographic database of over 4,000,000 records covering all aspects of agriculture and related sciences. In addition to free access via the National Agricultural Library's web site, AGRICOLA is available through a variety of vendors. To help librarians understand the different versions of AGRICOLA, this article compares access through CSA, Community of Science, FirstSearch, Ovid and SilverPlatter. Evaluation criteria include: search modes and limits allowed; display options; capacity to link to library catalog and document delivery services; ability to save, print, and/or e-mail search results; ability to save searches, or to search multiple databases; and availability of alert services. 相似文献
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Summary Principles of duplication within and between genebank collections have been explored, terminology is proposed and the difficulties
in identifying probable duplication are discussed.
Identical duplication concerns genetically identical accessions, whereas common duplication refers to accessions derived from
the same original population that are mixtures of lines with differing genotype frequencies, or random mating populations
with the same alleles but differing allele frequencies. Partial and compound duplication are types of incomplete duplication.
An additional type of duplication is the relation between the parents in a cross and their offspring, i.e. parental duplication.
Identifying probable duplication on the basis of passport data is often hindered by their incompleteness or poor quality.
The genetic identity of accessions is also subject to changes during maintenance in genebanks. Therefore, probable duplicates
will often not be true duplicates.
Examples from the European Barley Database illustrate the problems. 相似文献
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从促进无公害农产品流通,提高认证产品信息服务质量出发,该文以无公害农产品目录为研究对象,以实现认证产品信息的个性化检索与推荐为目标,进行产品目录智能服务的关键技术研究。以产品概念、属性和语义关系为主体,设计产品目录本体模型,建立产品目录领域本体,形成无公害农产品电子化目录;基于产品目录领域本体,从本体概念层面进行用户兴趣特征建模,采用语义清晰度与用户兴趣度的综合值设置概念权值,建立个性化产品目录加权本体模型,并设计个性化产品目录加权本体建立算法,实现用户兴趣的动态、准确和全面描述;通过个体过滤、综合过滤、概念映射、语义查询扩展和查询结果优化,构建个性化产品目录信息推荐与检索算法,建立产品目录智能服务系统。在检索结果用户满意度对比试验中,相比于基于领域本体检索、基于语义相似度优化检索和基于个性化本体优化检索3种方式,分别提高了31%、21%和14%,结果表明可在一定程度上提高无公害农产品目录信息检索推荐的质量和满意度,满足个性化的需求,同时也可为无公害农产品推广、品牌化销售和电子化交易提供技术支撑,具有较好的应用前景。 相似文献
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《CATENA》2005,63(1):39-63
The Monegros desert and its saline wetlands, called saladas (literally translated as “the salties”), are a unique European landscape of great scientific and ecological value. The saladas (i.e., playa-lakes and other small saline depressions) are dynamic environments; changing their surface morphology on a seasonal–diurnal basis in response to both climate and groundwater fluxes. To depict changes in these natural systems, we have identified five surface facies classes which are detectable both in the field and from remote sensing data. These facies are crucial for describing and promoting the protection of these habitats. Remote sensing has provided worthwhile historical data and additional information that compensate for scarce field records. Combined field and satellite criteria are used to catalog these facies with a new conceptual integration that manages the asynchronism between the field and satellite data. The catalog of facies is intended to be helpful for monitoring these wetlands, and for understanding the current hydrological patterns and trends in the playa-lakes. This work will serve as a baseline for studying the future evolution of the saladas which may soon fall under manmade environmental forces such as increased water input from adjacent newly irrigated lands. It is hoped that identification of these facies will be useful, with minor adaptations, in using more advanced sensors or in studying similar habitats. 相似文献
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Natalia N. Luneva Irena G. Chukhina Elizaveta G. Lebedeva 《Genetic Resources and Crop Evolution》2000,47(2):147-152
The herbarium collection of the N.I. Vavilov Institute of Plant Industry (WIR) contains specimens of cultivated plants, their wild relatives and weedy plants and provides ample opportunities for research. It is a unique special herbarium collection and one of those rare collections having a card index (catalog). For the catalog to be functional, it should reflect the current changes in the taxa names. Only a computerized card file may meet this requirement. The creation of a database for VIR's herbarium was launched in 1995. VIR is carrying out a range of work necessary for providing a wider access to its herbarium and related information for the international scientific community. 相似文献