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