Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
sach thu » sach thue, sach thieu, sach tham
vat hanh » vat thanh, van hanh, va hanh
sach ty » sach y, sach tu, xach tay
tang ma » mang may, tang van
vien da » vien dai, hien dai
da thuc » dan thuc, dai thuc, dam thuc
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)) tang ma hoi. hieu vien da thuc vat hanh vi cua vat~.
• Adding a wildcard symbol may retrieve word variants: su ((sach ty) or (sach thu)) tang ma hoi. hieu vien da thuc vat hanh vi cua vat*.