Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
cam truc » cau truc, nam truc, lam truoc
mai khoi » mai khoa, tai khoa, dai khoa
cac khoi » cac thoi, cac khoan, cach thoi
vai cua » dai cua, hai cua, lai cua
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
su sach » so sach, vu sach
qua cam » qua cham, qua cac, qua ca
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang

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 v nang ((mai khoi) OR (cac khoi)). hieu qua cam truc ((va hanh) or (va danh)) vai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach v nang ((mai khoi) OR (cac khoi)). hieu qua cam truc ((va hanh) OR (va danh)) vai cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach v nang ((mai khoi) OR (cac khoi)). hieu qua cam truc ((va hanh) or (va danh)) vai cua viet".
• Adding a wildcard symbol may retrieve word variants: su sach v nang ((mai khoi) OR (cac khoi)). hieu qua cam truc ((va hanh) or (va danh)) vai cua viet*.