Perhaps you should try some spelling variations:
ban thanh » ban hanh
ban hang » ngan hang
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
cam duc » cam xuc, cao duc, pham duc
sach ky » sach y, sach ty, sach kem
hieu ve » hieu va, hieu van
nang ma » tang ma, sang ma, nang cao
sac ky » cac ky, sai ky
ve cam » ve cham, ve cac, va cam

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) OR (sac ky)) nang ma hoa. hieu ve cam 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) OR (sac ky)) nang ma hoa. hieu ve cam duc ((ban thanh) OR (ban hang)) vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ky) OR (sac ky)) nang ma hoa. hieu ve cam duc ((ban thanh) or (ban hang)) vai cua tre".
• Adding a wildcard symbol may retrieve word variants: te ((sach ky) OR (sac ky)) nang ma hoa. hieu ve cam duc ((ban thanh) or (ban hang)) vai cua tre*.