商业类搜索引擎及目录索引

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化学工业 Chemicals：

Chemical World - A portal which guides you through the world of the chemical industry: chemistry, fuel cell, explosives, polymers, biochemistry etc.

ChemIndustry.com - Worldwide search engine of the chemical industry - search for chemicals, equipment, services and chemical information.

PSI - Polymer Search on the Internet - Search engine for the global polymer, plastic and rubber industries. Includes daily industry news.