Perhaps you should try some spelling variations:
"model factors" » "models factors", "model factor", "model factory"
"mode factor" » "model factor", "models factor", "model factory", "mode facto", "moe factor", "modose factor", "mode factoor", "mode faitor"
"de factor" » "de facto", "e factor", "dose factor", "de factoor", "de faitor"
"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 fact") OR ((("de factor") OR ((("mode factor") OR ("model factors")))))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"de fact\") or (((\"de factor\") or (((\"mode factor\") OR (\"model factors\"))))))".
• Removing quotes may allow a broader search: (( de fact ) or ((( de factor ) or ((( mode factor ) OR ( model factors )))))).
• Adding a wildcard symbol may retrieve word variants: (("de fact") or ((("de factor") or ((("mode factor") OR ("model factors"))))))*.