Perhaps you should try some spelling variations:
"institutionalisierung qr codes" » "institutionalisierung zur codes", "institutionalisierung _ codes", "institutionalisierung im codes", "institutionalisierung qr code"
"institutionalisierung der kodes" » "institutionalisierung der codes", "institutionalisierung der kodex", "institutionalisierung der koder"

Try widening your search to All Fields.

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: (("institutionalisierung der kodes") OR ("institutionalisierung qr codes")).
• Removing quotes may allow a broader search: (( institutionalisierung der kodes ) or ( institutionalisierung qr codes )).
• Adding a wildcard symbol may retrieve word variants: (("institutionalisierung der kodes") or ("institutionalisierung qr codes"))*.