The author reviews the application,development and existing problems of the descriptor language since the realization of computerized information retrieval.The future trend of the descriptor language is also discussed so as to promote the development of information retrieval language and improve the function of the retrieval systems.

The problem of word combination in IR system with word index was discussed and an abstract structure on word index was put forward in the paper.Four kinds of algorithems of word combination were proposed,compared and analysed.

The article briefly describes the system of automatic astracting of Chinese documents as well as the main ideas for designing such system.

A detailed description is given of the information retrieval system for Chinese patents,which includes the operation environment,the system construction,the retrieval functions,the information contents and the data format.This retrieval system is implemented by VSAM file management system,making a feature of file creation,update,the realization of retrieval functions and the improvement of the retrieval performances as well.

This paper presents a model of determining automatically the classification notation of documents by keywords.The classifying algorithm and,data structure are given for enumerative and faceted classifications.

Aimed at overcoming the disadvantages of Fukujima algorithm and its improvements,the author put forward a new reversed polish retrospective scanning algorithm with tree expanding algorithm correcting errors while overflowing.The outcome shows that the mixed algorithm is satisfying considering its speed of data handling and efficiency of memory allocating.

ORACLE is a ideal tool in developing library management information system.With the experience the author obtained in system development using ORACLE v.5 1,the common methods and some technical problems for the development of computerized library system are discussed in this article.