Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh vai » thanh hai, thanh van, thanh tai
hieu van » hieu va, thien van, lieu va
sach ty » sach y, sach tu, sach thu
sang ma » tang ma, nang ma, sang tao
bay dia » tay dia
ban dia » ban da, ban dich, ban chia
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((cac ky) or (sach ty)) sang ma hoi. hieu van ((bay dia) OR (ban dia)) ban thanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((cac ky) OR (sach ty)) sang ma hoi. hieu van ((bay dia) OR (ban dia)) ban thanh vai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((cac ky) or (sach ty)) sang ma hoi. hieu van ((bay dia) OR (ban dia)) ban thanh vai cua tre*".