information or retrieval -
same as above
information and retrieval -
finds pages containing both "information" and "retrieval"
information not retrieval -
finds pages containing "information' but not 'retrieval"
(information not retrieval) and WAIS -
finds pages containing "WAIS" and "information" but not "retrieval"
web* - uses a "wildcard" (*) to find documents containing words starting with "web..."