Perhaps you should try some spelling variations:
"nijhoff boston titles 21" » "nijhoff boston tables 21", "nijhoff boston times 21", "nijhoff boston entitled 21", "nijhoff boston titles 1", "nijhoff boston titles 11", "nijhoff boston titles 2.9"
"nijhoff book intitled 71" » "nijhoff book intituled 71", "nijhoff book entitled 71", "nijhoff op intitled 71", "nijhoff book intitled 1", "nijhoff book intitled _", "nijhoff book intitled a"
"nijhoff book titles 71" » "nijhoff op titles 71", "nijhoff book entitled 71", "nijhoff book tables 71", "nijhoff work titles 71", "nijhoff book times 71", "nijhoff book titles 1", "nijhoff book titles 11", "nijhoff book titles 78"
"nijhoff book title 21" » "nijhoff op title 21", "nijhoff book table 21", "nijhoff work title 21", "nijhoff book time 21", "nijhoff book title 1", "nijhoff book title 2", "nijhoff book title _"
"nijhoff ebook title 2006" » "nijhoff ebook title 26", "nijhoff ebook title 20", "nijhoff ebook title 2012", "nijhoff ebook table 2006", "nijhoff ework title 2006", "nijhoff ebook time 2006"
"nijhoff ebola time 2006" » "nijhoff ebola time 2000", "nijhoff ebola time 2001", "nijhoff ebola time 2004"

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: (((("nijhoff ebook title 2006") OR ("nijhoff ebola time 2006"))) OR ((((((("nijhoff book titles 71") OR ("nijhoff book intitled 71"))) OR ("nijhoff boston titles 21"))) OR ("nijhoff book title 21")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"nijhoff ebook title 2006\") or (\"nijhoff ebola time 2006\"))) or (((((((\"nijhoff book titles 71\") OR (\"nijhoff book intitled 71\"))) or (\"nijhoff boston titles 21\"))) or (\"nijhoff book title 21\"))))".
• Removing quotes may allow a broader search: (((( nijhoff ebook title 2006 ) or ( nijhoff ebola time 2006 ))) or ((((((( nijhoff book titles 71 ) OR ( nijhoff book intitled 71 ))) or ( nijhoff boston titles 21 ))) or ( nijhoff book title 21 )))).
• Adding a wildcard symbol may retrieve word variants: (((("nijhoff ebook title 2006") or ("nijhoff ebola time 2006"))) or ((((((("nijhoff book titles 71") OR ("nijhoff book intitled 71"))) or ("nijhoff boston titles 21"))) or ("nijhoff book title 21"))))*.