Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
tang ma » tang van
viec da » viec dat, vien da, viec va
va hanh » van hanh, va thanh, va danh
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.

• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((tang ma) OR (mang may)) hoa. hieu viec da tuc va hanh vi cua vat~".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((tang ma) OR (mang may)) hoa. hieu viec da tuc va hanh vi cua vat*.