Perhaps you should try some spelling variations:
"blended theory" » "extended theory", "blending theory", "blended query"
"bands theory" » "band theory", "bang theory", "minds theory"
"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 ((("blended theory") OR ("bands theory")))).
• Removing quotes may allow a broader search: (( grounded theory ) or ((( blended theory ) or ( bands theory )))).
• Adding a wildcard symbol may retrieve word variants: (("grounded theory") or ((("blended theory") or ("bands theory"))))*.