Perhaps you should try some spelling variations:
"nijhoff book title 21" » "nijhoff boston title 21", "nijhoff op title 21", "nijhoff book titles 21", "nijhoff ebook title 21", "nijhoff book table 21", "nijhoff book title 1", "nijhoff book title 2", "nijhoff book title _"
"nijhoff app title 25" » "nijhoff op title 25", "nijhoff a title 25", "nijhoff app title 2", "nijhoff app title 5", "nijhoff app title 26"

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: (("nijhoff app title 25") OR ("nijhoff book title 21")).
• Removing quotes may allow a broader search: (( nijhoff app title 25 ) or ( nijhoff book title 21 )).
• Adding a wildcard symbol may retrieve word variants: (("nijhoff app title 25") or ("nijhoff book title 21"))*.