Perhaps you should try some spelling variations:
"2 original conference" » "2 regional conference", "2 retinal conference", "2 regional conferences", "_ original conference", "2 origins conference", "2 origin conference"
"das original conference" » "das regional conference", "das retinal conference", "das regional conferences", "his original conference", "its original conference"

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: (("2 original conference") OR ("das original conference")).
• Removing quotes may allow a broader search: (( 2 original conference ) or ( das original conference )).
• Adding a wildcard symbol may retrieve word variants: (("2 original conference") or ("das original conference"))*.