Perhaps you should try some spelling variations:
"world apps technical paper" » "world apps technical papers", "world app technical paper", "world apis technical paper", "world basics technical paper"
"world a technical paper" » "world a technical papers"

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: (("world apps technical paper") OR ("world a technical paper")).
• Removing quotes may allow a broader search: (( world apps technical paper ) or ( world a technical paper )).
• Adding a wildcard symbol may retrieve word variants: (("world apps technical paper") or ("world a technical paper"))*.