Perhaps you should try some spelling variations:
"grounded theory8.1" » "grounded theory", "grounded theorie", "grounded theories"
"grounded theory6" » "grounded theory", "grounded theorie", "grounded theories"
"founded theory" » "grounded theory", "founding theory", "coupled 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: (("founded theory") OR ((("grounded theory6") OR ("grounded theory8.1")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"founded theory\") or (((\"grounded theory6\") OR (\"grounded theory8.1\"))))".
• Removing quotes may allow a broader search: (( founded theory ) or ((( grounded theory6 ) OR ( grounded theory8.1 )))).
• Adding a wildcard symbol may retrieve word variants: (("founded theory") or ((("grounded theory6") OR ("grounded theory8.1"))))*.