The component factors of on-line search process can be approached as man-machine system. Based on the system theory, its effectiveness in information on-line search is affected by man-machine-environment. The author emphatically analyses such impacts on the system effectiveness as user's psychology, searcher's psychological factor, retrieval language, thesaurus, and environment. Meanwhile, the article puts forward some tentative ideas to improve the system effectiveness, such as adopting mixed retrieval language system, letting users get ...
