Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
sach thu » sach thue, sach thieu, sach tham
sach ty » sach y, sach tu, xach tay
va hanh » van hanh, va thanh, va danh
vien da » vien dai, hien dai
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
da tuc » dao tuc, va tuc, da tac
tuc va » thuc va, truc va, tuc xa
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)) ((nang ma) OR (tang ma)) hoi. hieu vien da tuc va hanh vi cua vat~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ty) OR (sach thu)) ((nang ma) or (tang ma)) hoi. hieu vien da tuc va hanh vi cua vat~".
• Adding a wildcard symbol may retrieve word variants: su ((sach ty) OR (sach thu)) ((nang ma) or (tang ma)) hoi. hieu vien da tuc va hanh vi cua vat*.