Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
vien dai » hien dai
sach thu » sach thue, sach thieu, sach tham
vat hanh » vat thanh, van hanh, nhat hanh
dai thuc » dan thuc, dai thu, dai thua
va hanh » van hanh, va thanh, va danh
sach uu » sach luu, sach tu, sach xu
hang ma » hang va, hang ca, tang ma
vai cua » dai cua, hai cua, lai cua
ma hoi » mai hoi, xa hoi, ma hoa

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach uu) OR (sach thu)) hang ma hoi. hieu vien dai thuc ((vat hanh) OR (va hanh)) vai cua vat~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach uu) or (sach thu)) hang ma hoi. hieu vien dai thuc ((vat hanh) OR (va hanh)) vai cua vat~".
• Adding a wildcard symbol may retrieve word variants: su ((sach uu) or (sach thu)) hang ma hoi. hieu vien dai thuc ((vat hanh) OR (va hanh)) vai cua vat*.