Perhaps you should try some spelling variations:
cham quoc » chuan quoc, han quoc, cham soc
ban hanh » ban hang
ban xanh » ban anh, ban banh, ban danh
cua tre » cua te, cuu tre, cua triet
ve cham » va cham, ve chat, vu cham
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ky sang » ky nang, ky dang, ky tang
sac ky » cac ky, sai ky
ma hoi » xa hoi, ma hoa, me hoi
di cua » dai cua, doi cua, de cua
tu sac » tu sach, tu cac, tu san

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky sang ((ma hoi) or (mai hoi)). hieu ve cham quoc ((ban xanh) OR (ban hanh)) di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky sang ((ma hoi) OR (mai hoi)). hieu ve cham quoc ((ban xanh) OR (ban hanh)) di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky sang ((ma hoi) or (mai hoi)). hieu ve cham quoc ((ban xanh) OR (ban hanh)) di cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sac ky sang ((ma hoi) or (mai hoi)). hieu ve cham quoc ((ban xanh) OR (ban hanh)) di cua tre*.