The paper studies course scope, retrieval functions, retrieval technique, document export of the database retrieval systems, analyses the general and specific character, and points out the shortages.

本文对数据库检索系统的学科范围、检索功能、检索技术、文献输出等进行比较研究，分析其共性与个性，指出其不足。

youdao

The story starts back in January 1998, when Royal Ordinance, now part of BAe Systems, applied for an export licence to refurbish the 30 Moroccan guns in Western Sahara and also, according to a confidential document we have seen, supply six new guns.

BBC: News Online