Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
hieu viec » nhieu viec, hieu ve, sieu viet
viec cam » viec lam, viec cua, viec va
van hanh » ban hanh, van anh, van ban
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
cua tre » cua te, cuu tre, cua triet
co hoi » co hoc, co loi
o hoi » o hoc, o hai, o hoa

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 hoi)). hieu viec cam xuc ((van hanh) or (van thanh)) tri cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((o hoi) OR (co hoi)). hieu viec cam xuc ((van hanh) OR (van thanh)) tri cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((o hoi) or (co hoi)). hieu viec cam xuc ((van hanh) or (van thanh)) tri cua tre*.