Perhaps you should try some spelling variations:
su sach » so sach, vu sach
sach tu » sach thu, cach tu, sach ty
tu nang » tru nang, tu nong, tu nano
cao hoc » co hoc, chat hoc
cho hoc » co hoc, khoa hoc
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac dac
va hanh » van hanh, va thanh, va danh
vai cua » dai cua, hai cua, lai cua
vi cua » di cua

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 tu nang ((cao hoc) OR (cho hoc)). hieu va cac duc va hanh ((vi cua) or (vai cua)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach tu nang ((cao hoc) OR (cho hoc)). hieu va cac duc va hanh ((vi cua) OR (vai cua)) viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach tu nang ((cao hoc) OR (cho hoc)). hieu va cac duc va hanh ((vi cua) or (vai cua)) viet*".