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