Perhaps you should try some spelling variations:
dang hai » dang khai, hang hai, dung hai
thu sach » tu sach, thuat sach, thuoc sach
tu cach » tu cac
nang xa » lang xa, nang ma, mang xa
va dang » van dang, va nang, va lang
hac xuc » chat xuc
xuc va » duc va, tuc va, luc va
va hac » van hac, va khac, va cac
hai va » hai van, thai va, hoi va
thiet » thieu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu cach) or (thu sach)) tru ((nang xa) OR (nang x)) hoi. lieu va hac xuc va dang hai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cach) OR (thu sach)) tru ((nang xa) OR (nang x)) hoi. lieu va hac xuc va dang hai va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu cach) or (thu sach)) tru ((nang xa) OR (nang x)) hoi. lieu va hac xuc va dang hai va thiet".
• Adding a wildcard symbol may retrieve word variants: ((tu cach) or (thu sach)) tru ((nang xa) OR (nang x)) hoi. lieu va hac xuc va dang hai va thiet*.