一、灰色文献及其特点　　灰色文献是信息时代中最为引人注目的一种特殊文献，是一种介于黑白文献之间的不公开发行的文献。它通常是指那些没有公开出版的各种政府内部报告；科研情报机构内部出版物；各种会议资料以及未发表的论文，也包括政府文书、文件、调研报告；还档案文 First, the gray literature and its characteristics Gray literature is the most eye-catching special information in the information age, is a black-and-white document between the non-public offering of literature. It generally refers to various government internal reports that are not published in public; internal publications of research intelligence agencies; various conference materials and unpublished papers, including government documents, papers, research reports; and archives