Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
van hanh » van thanh, ban hanh, van anh
sach thu » sach thue, sach thieu, sach tham
dam thuc » am thuc, dan thuc, nam thuc
da thuc » dan thuc, dai thuc, day thuc
sach ty » sach y, sach tu, xach tay
hang ma » hang va, hang ca, tang ma
ma hoi » mai hoi, xa hoi, ma hoa
vi cua » vai cua, di cua

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 ty) OR (sach thu)) hang ma hoi. hieu vien ((da thuc) OR (dam thuc)) van hanh vi cua vat~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ty) or (sach thu)) hang ma hoi. hieu vien ((da thuc) OR (dam thuc)) van hanh vi cua vat~".
• Adding a wildcard symbol may retrieve word variants: su ((sach ty) or (sach thu)) hang ma hoi. hieu vien ((da thuc) OR (dam thuc)) van hanh vi cua vat*.