Perhaps you should try some spelling variations:
"grounded theory6" » "grounded theorie", "grounded theory8.1", "grounded theories"
"founding theory" » "bounding theory", "grounding theory", "folding theory"
"founded theory" » "founded where", "sound theory", "blended theory"
"coupled theory" » "coupling theory", "coupled thermo", "coupled memory"

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 ("founding theory"))) OR ("coupled theory"))) OR ("grounded theory6")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"grounded theory\") or (((((((\"founded theory\") OR (\"founding theory\"))) or (\"coupled theory\"))) or (\"grounded theory6\"))))".
• Removing quotes may allow a broader search: (( grounded theory ) or ((((((( founded theory ) OR ( founding theory ))) or ( coupled theory ))) or ( grounded theory6 )))).
• Adding a wildcard symbol may retrieve word variants: (("grounded theory") or ((((((("founded theory") OR ("founding theory"))) or ("coupled theory"))) or ("grounded theory6"))))*.