Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
va thanh » gia thanh, ban thanh, va tinh
hieu van » hieu va, thien van, lieu va
sach ky » sac ky, sach y, sach kem
hac dat » hoc dat, tac dat, hoach dat
van hac » van hoc, van ha, van hai
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
sach ty » sach y, sach tu, sach thu
vai cua » dai cua, hai cua, lai cua

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) or (sach ty)) ((nang ma) OR (tang ma)) hoi. hieu van hac dat va thanh vai cua vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ky) OR (sach ty)) ((nang ma) OR (tang ma)) hoi. hieu van hac dat va thanh vai cua vat.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ky) or (sach ty)) ((nang ma) OR (tang ma)) hoi. hieu van hac dat va thanh vai cua vat".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ky) or (sach ty)) ((nang ma) OR (tang ma)) hoi. hieu van hac dat va thanh vai cua vat*.