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顾震宇  路炜 《图书馆杂志》2006,25(11):40-44
本文基于Dialog联机检索,以德温特世界专利索引数据库和专利引文索引数据库为数据源,对质子交换膜(PEM)燃料电池行业进行了专利分析研究。作者用实例说明了利用各种Dialog高级检索指令实现行业专利分析的技巧。通过分析研究,发现了PEM燃料电池行业的领先企业、技术领军人物、产业发展前景、全球技术/市场布局、关键技术、研发热点等。研究表明,Dialog?联机检索在行业专利分析中是一种有效的工具。  相似文献   
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Serum vitamin E and cholesterol concentrations were measured in 50 children with protein energy malnutrition (PEM) and results were compared with a group of 50 normal controls. Mean serum vitamin E concentration as well as vitamin E/cholesterol ratio were found to be reduced in children with PEM while their mean serum cholesterol level was not significantly different from the control group. Data suggest that the reduced levels of serum vitamin E in PEM may be a result of malnutrition per se.  相似文献   
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INTRODUCTION Water management is one of the critical opera-tion issues in proton exchange membrane (PEM) fuelcells. Spatially varying concentrations of water inboth vapour and liquid form are expected throughoutthe cell because of varying rates of production andtransport (Sui and Djilali, 2005). Devising betterwater management is therefore a key issue in PEMFCdesign, and this requires improved understanding ofthe parameters affecting water transport in the mem-brane. Proper thermal m…  相似文献   
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Single‐subject experimental research (SSER), one of the most commonly used research methods in special education and applied behaviour analysis, is a scientific, rigorous and valid method to evaluate the effectiveness of behavioural, educational and psychological treatments. However, studies using single‐subject experimental research designs are often excluded from meta‐analyses of evidence‐based practices due to the lack of methodological consensus on the type of effect size indices to be used to determine treatment effect. To promote the use of effect size indices as an adjunct to visual analysis, this article describes four nonoverlap methods (PND, IRD, PEM‐T and Tau‐U) and demonstrates their application to data obtained from studies employing different SSER designs. Advantages and disadvantages of each method are highlighted and considerations for selecting the most appropriate method are provided for researchers and practitioners.  相似文献   
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