Perhaps you should try some spelling variations:
hieu vien » hieu hien, hieu viec, thieu nien
hanh thai » nhanh thai, hinh thai, hanh tai
van hanh » van thanh, ban hanh, van anh
thai cua » than cua, tai cuc, tri cua
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
cac xuc » cac nuoc, chat xuc, cac cuoc
cua tre » cua te, cuu tre, cua triet
co hoi » co loi

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 ky nang ((co hoi) OR (co hoc)). hieu vien ((cac xuc) OR (cam xuc)) van hanh thai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((co hoi) or (co hoc)). hieu vien ((cac xuc) OR (cam xuc)) van hanh thai cua tre~".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((co hoi) or (co hoc)). hieu vien ((cac xuc) OR (cam xuc)) van hanh thai cua tre*.