Perhaps you should try some spelling variations:
ban thanh » ban hang
hieu van » hieu va, thien van, lieu va
ban hanh » ban hang
tu sach » thu sach, su sach, te sach
nam qua » nam quan, nam cua, nam mua
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, me hoi

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 y nang ((ma hoi) or (ma hoa)). hieu van nam qua ((ban thanh) or (ban hanh)) vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((ma hoi) OR (ma hoa)). hieu van nam qua ((ban thanh) OR (ban hanh)) vai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((ma hoi) or (ma hoa)). hieu van nam qua ((ban thanh) or (ban hanh)) vai cua tre*.