Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dinh dai » dinh dat, sinh dai, dinh dao
tu sach » thu sach, su sach, te sach
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
hieu ve » hieu va, hieu van
cau luc » cau truc, cau phuc
va dinh » van dinh, va kinh, va tinh
ve cau » ke cau, va cau, ve cac
luc va » duc va, tuc va, loc va
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (toc sach)) ky tang xa hoi. hieu ve cau luc va dinh dai cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (toc sach)) ky tang xa hoi. hieu ve cau luc va dinh dai cua tu.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (toc sach)) ky tang xa hoi. hieu ve cau luc va dinh dai cua tu*.