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