Perhaps you should try some spelling variations:
sach thue » sach thu, sach thieu, sach tham
thue nang » thien nang, thuat nang, thi nang
hieu vien » hieu hien, hieu viec, thieu nien
nang cau » nang cao, hang cau, nang dau
thuc dan » thuc hanh, hoc dan
su sach » so sach, vu sach
vien da » vien dai, hien dai
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 thue nang cau hoi. hieu vien da ((thuc dan) OR (thuc vat)) hanh vi cua vat~.
• Adding a wildcard symbol may retrieve word variants: su sach thue nang cau hoi. hieu vien da ((thuc dan) or (thuc vat)) hanh vi cua vat*.