The scientifically categorized databases of various corporations and manufacturers of the world most popular and 7 biggest online retrieval systems have been made available by the author for all end users for fast effective and correct access to any required databases 摘要本文根据《中国图书分类法》的原理与规则，对世界最为通用的七大国际联机检索系统中的众多的公司（厂商）信息库进行了科学的分类，为用户准确快速地选择所需数据库提供了方便。
