Perhaps you should try some spelling variations:
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
danh doi » danh di, thanh doi, dung doi
so sach » so sanh, bo sach, co sach
cac toc » cac toi, cac thoi
doi cua » dai cua, hoi cua
xa danh » va danh, dia danh, nam danh
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ma hoi » xa hoi, ma hoa, me hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky nang ((ma hoi) or (mai hoi)). hieu ve ((cac toc) OR (cac nuoc)) xa danh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang ((ma hoi) OR (mai hoi)). hieu ve ((cac toc) OR (cac nuoc)) xa danh doi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky nang ((ma hoi) or (mai hoi)). hieu ve ((cac toc) OR (cac nuoc)) xa danh doi cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach ky nang ((ma hoi) or (mai hoi)). hieu ve ((cac toc) OR (cac nuoc)) xa danh doi cua tre*.