Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
can nuoc » cap nuoc, can cuoc, chan nuoi
cua viet » ca viet, hoa viet, cua vat
lai hoi » dai hoi, lai hoa, lai roi
sach ty » sach y, sach tu, sach thu
mai hoi » mai khoi, dai hoi, mai doi
ty nang » ky nang, ty xang, ty hang
va hanh » van hanh, va thanh, va danh
tu sach » thu sach, su sach, te sach
vi cua » vai cua, di cua

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: tu sach ty nang ((mai hoi) OR (lai hoi)). hieu viec ((can nuoc) OR (cac nuoc)) va hanh vi cua viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang ((mai hoi) or (lai hoi)). hieu viec ((can nuoc) OR (cac nuoc)) va hanh vi cua viet~".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((mai hoi) or (lai hoi)). hieu viec ((can nuoc) OR (cac nuoc)) va hanh vi cua viet*.