Perhaps you should try some spelling variations:
"de factor" » "e factor", "dose factor", "mode factor", "de factr", "de factsr"
"de factr" » "de facteur", "de fazer", "de fair"
"de facon" » "de falco", "la facon", "en facon"
"de facto" » "de fact", "de facts"

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (("de facto") OR ((("de factor") OR ((("de factr") OR ("de facon")))))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"de facto\") or (((\"de factor\") or (((\"de factr\") OR (\"de facon\"))))))".
• Removing quotes may allow a broader search: (( de facto ) or ((( de factor ) or ((( de factr ) OR ( de facon )))))).
• Adding a wildcard symbol may retrieve word variants: (("de facto") or ((("de factor") or ((("de factr") OR ("de facon"))))))*.