Perhaps you should try some spelling variations:
"bounded theory" » "bounds theory", "bounded theories", "grounded theory6"
"blended theory" » "extended theory", "blending theory", "blended query"
"grounded theory" » "ground theory", "founded 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 ((("bounded theory") OR ("blended theory")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"grounded theory\") or (((\"bounded theory\") OR (\"blended theory\"))))".
• Removing quotes may allow a broader search: (( grounded theory ) or ((( bounded theory ) OR ( blended theory )))).
• Adding a wildcard symbol may retrieve word variants: (("grounded theory") or ((("bounded theory") OR ("blended theory"))))*.