Perhaps you should try some spelling variations:
"founded theory" » "grounded theory6", "founding theory", "coupled theory"
"ground theory" » "group theory", "grand theory", "sound theory"
"groups theory" » "group theory", "groups other"
"grounded theory" » "bounded theory"

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: (((("grounded theory") OR ("founded theory"))) OR ((("ground theory") OR ("groups theory")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"grounded theory\") OR (\"founded theory\"))) or (((\"ground theory\") or (\"groups theory\"))))".
• Removing quotes may allow a broader search: (((( grounded theory ) OR ( founded theory ))) or ((( ground theory ) or ( groups theory )))).
• Adding a wildcard symbol may retrieve word variants: (((("grounded theory") OR ("founded theory"))) or ((("ground theory") or ("groups theory"))))*.