1. A method for searching databases, comprising: converting plain-language text in various fields of an input document into a plurality of surrogate vectors each comprising a digital binary word; and translating particular plain-language words or character strings included in said text into corresponding distinct ones of said surrogate vectors; wherein, each distinct plain-language word or character string sets a particular group of bits true in said surrogate vectors, and each surrogate vector is encoded with more that one such distinct plain-language word or character string.