Perhaps you should try some spelling variations:
"coupled theory" » "coupling theory", "coupled thermo", "coupled memory"
"ground theory" » "group theory", "groups theory", "grand theory"
"grounded theory" » "founded 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 ("ground theory"))) OR ("coupled theory")).
• Removing quotes may allow a broader search: (((( grounded theory ) or ( ground theory ))) or ( coupled theory )).
• Adding a wildcard symbol may retrieve word variants: (((("grounded theory") or ("ground theory"))) or ("coupled theory"))*.