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