Perhaps you should try some spelling variations:
ban thanh » ban hanh
ban hang » ngan hang
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
van hoe » van hoc, van hieu, van hien
hieu va » lieu va, hieu qua
am hoc » ad hoc
do cua » doi cua, co cua, de cua
cua te » cua tu
va am » va lam, va cam

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang ((van hoa) or (van hoe)). hieu va am hoc ((ban thanh) OR (ban hang)) do cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((van hoa) OR (van hoe)). hieu va am hoc ((ban thanh) OR (ban hang)) do cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((van hoa) or (van hoe)). hieu va am hoc ((ban thanh) OR (ban hang)) do cua te".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((van hoa) or (van hoe)). hieu va am hoc ((ban thanh) OR (ban hang)) do cua te*.