Perhaps you should try some spelling variations:
quoc quan » qua quan, luc quan, hoc quan
quoc lan » quoc ban, nuoc luan, quoc danh
cuu tre » cua tre, cau tren, cau treo
xanh di » danh di, vanh dai, xanh tai
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 cuu » di cau, di cua, dinh cuu
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 quan) or (quoc lan)) xanh di cuu 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 quan) OR (quoc lan)) xanh di cuu 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 quan) or (quoc lan)) xanh di cuu tre*".