Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
cao khoa » lao khoa, bao khoa, cac khoa
viec cac » vien cac, viec cua, viec lam
cac thoi » cac toi, cac hop, cac tro
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
cao hoa » cao hoat, cau hoa, cao hoc
thoi va » hoi va, thai va, tho va
va hang » van hang, va nang, va lang
hang di » hang doi, hang vi, hang dien
cua tre » cua te, cuu tre, cua triet
di cua » dai cua, doi cua, de cua

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 ((cao hoa) or (cao khoa)). hieu viec cac thoi va hang di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((cao hoa) OR (cao khoa)). hieu viec cac thoi va hang di cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((cao hoa) or (cao khoa)). hieu viec cac thoi va hang di cua tre*.