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