Bartlett's is also available in a web edition. Columbia World of Quotations 65,000 quotations on 6,500 subjects. Searchable by subject, author, source or natural language searching. Provides context of quote. Gale's Quotations Over 117,000 quotations, most with a short biographical sketch of the speaker.
Users can also browse list of quotations.
Extended search functions allows searching by source, occupation of speaker, nationality, facts about the speaker, birth year or death year. In DOS, Boolean searchable. Oxford English Dictionary Has a word look up function, can also search in text, etymology, Greek, and phonetic searching. Also has a wildcard search mode, for unknown letters. The OED is online, but requires a password to use.