Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
viec cac » vien cac, viec cua, viec lam
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
cac xuc » cam xuc, cac nuoc, chat xuc
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
o hoi » co hoi, o hoc, o hai
tuan » quan, tran, luan

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky nang ((o hoi) or (co hoc)). hieu viec cac xuc ((van hanh) or (tuan anh)) tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((o hoi) OR (co hoc)). hieu viec cac xuc ((van hanh) OR (tuan anh)) tai cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((o hoi) or (co hoc)). hieu viec cac xuc ((van hanh) or (tuan anh)) tai cua tre*.