Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
vai cua » dai cua, hai cua, lai cua
cay cua » ca cua, day cua, cay ca
van cay » van cau, van bay, van ca
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach kem
sach ty » sach y, sach tu, sach thu
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: su ((sach ky) OR (sach ty)) nang ((ma hoi) or (ma hoa)). hieu van cay cua ban thanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach ty)) nang ((ma hoi) OR (ma hoa)). hieu van cay cua ban thanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) OR (sach ty)) nang ((ma hoi) or (ma hoa)). hieu van cay cua ban thanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) OR (sach ty)) nang ((ma hoi) or (ma hoa)). hieu van cay cua ban thanh vai cua tre*.