Perhaps you should try some spelling variations:
nhieu viec » nhien viet
cua triet » cua viet, su triet, va triet
hieu viec » hieu ve, sieu viet, hieu hien
cao hoat » cac hoat, co hoat, cao chat
va hang » van hang, va lang, va hanh
va nang » van nang, da nang, cam nang
tu sach » thu sach, su sach, te sach
y nang » ky nang, ly nang, v nang
cac tu » cac thu, cach tu, cac du
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y nang cao hoat. ((hieu viec) OR (nhieu viec)) cac tu ((va hang) or (va nang)) va cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang cao hoat. ((hieu viec) OR (nhieu viec)) cac tu ((va hang) OR (va nang)) va cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang cao hoat. ((hieu viec) OR (nhieu viec)) cac tu ((va hang) or (va nang)) va cua triet".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang cao hoat. ((hieu viec) OR (nhieu viec)) cac tu ((va hang) or (va nang)) va cua triet*.