灰色文献是一种内容复杂、信息量大、情报价值高的文献 ,因其独有的特性 ,已成为目前国内外图书情报界公认的重要信息资源之一。它在科技文献中占有一席之地。而科技查新中最重要的步骤是文献检索 ,即根据课题特点确定检索途径 ,利用检索工具进行手检或机检 ,以便查找所需的文? Gray literature is a kind of literature with complex content, large amount of information and high intelligence value. Due to its unique characteristics, gray literature has become one of the most important information sources recognized by the LISL at home and abroad. It has a place in the scientific literature. However, the most important step in the search for new technology is document retrieval, which means to determine the retrieval route according to the characteristics of the subject, to use manual or seized inspection tools to find the required documents.