Perhaps you should try some spelling variations:
ban thanh » ban hanh
thu sach » tu sach, thuat sach, thuoc sach
ban hang » ngan hang
hieu van » hieu va, thien van, lieu va
tang ma » mang may, tang van
sach ky » sac ky, sach y, sach ty
van cam » van nam, van lam, van cau
nang ma » sang ma, nang cao, mang may
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky ((nang ma) OR (tang ma)) hoi. hieu van cam xuc ((ban thanh) or (ban hang)) vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((nang ma) OR (tang ma)) hoi. hieu van cam xuc ((ban thanh) OR (ban hang)) vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky ((nang ma) OR (tang ma)) hoi. hieu van cam xuc ((ban thanh) or (ban hang)) vai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((nang ma) OR (tang ma)) hoi. hieu van cam xuc ((ban thanh) or (ban hang)) vai cua tre*.