Perhaps you should try some spelling variations:
"model factor" » "models factor", "model fast"
"de factor" » "de facto", "e factor", "dose factor", "de factoor", "de faitor"
"de faits" » "des faits", "de fait", "les faits"
"de fact" » "de facto", "de fait", "e fact"

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 factor") OR ("model factor"))) OR ("de faits"))) OR ("de fact")).
• Removing quotes may allow a broader search: (((((( de factor ) or ( model factor ))) or ( de faits ))) or ( de fact )).
• Adding a wildcard symbol may retrieve word variants: (((((("de factor") or ("model factor"))) or ("de faits"))) or ("de fact"))*.