Perhaps you should try some spelling variations:
ban thanh » ban hanh
ban hang » ngan hang
te sach » toc sach
vai cua » dai cua, hai cua, lai cua
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
sach ky » sac ky, sach y, sach ty
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
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: te sach ky ((nang ma) or (tang ma)) hoi. hieu ve pham duc ((ban thanh) or (ban hang)) vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky ((nang ma) OR (tang ma)) hoi. hieu ve pham duc ((ban thanh) OR (ban hang)) vai cua tre.
• Adding a wildcard symbol may retrieve word variants: te sach ky ((nang ma) or (tang ma)) hoi. hieu ve pham duc ((ban thanh) or (ban hang)) vai cua tre*.