著名的图书馆学家杜威(Dewey M.)早在半个世纪以前就说过:“以最少的费用为最多的读者提供最佳读物。”这一图书采购原则至今仍然适用。但是,随着时间的推移,要真正做到这一点,已经是越来越难了。这是因为:半个世纪以来,科学技术的飞速发展与进步,知识生产者与消费者数量的猛增,导致了图书文献量以指数形式迅速增长。仅以图书为例,美国1950年出版图书11022种,1960年为15012种, Well-known library scientist Dewey M. said as early as half a century ago: “The best readership is provided for the readers who have the most fees.” This principle of book procurement still applies today. However, over time, it has become increasingly difficult to do that. This is because: Over the past half century, the rapid development and progress of science and technology and the surge in the number of knowledge producers and consumers have led to an exponential increase in the volume of books and literature. Only books, for example, the United States published 11022 books in 1950, 15012 in 1960,