Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
nham thuc » nhan thuc, nam thuc, nham thu
sang mai » sang ma, sang tai, lang mai
cham tuc » pham thuc, tham thuc, cham soc
ky sang » ky nang, ky dang, ky tang
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, dua tren
tu sac » tu sach, tu cac, tu san
va don » va dong, va doc, va do
sac ky » cac ky, sai ky

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 mai hoi. hieu ve ((cham tuc) or (nham thuc)) va don vi ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky sang mai hoi. hieu ve ((cham tuc) OR (nham thuc)) va don vi ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky sang mai hoi. hieu ve ((cham tuc) or (nham thuc)) va don vi ((cua tre) OR (cua triet))".
• Adding a wildcard symbol may retrieve word variants: tu sac ky sang mai hoi. hieu ve ((cham tuc) or (nham thuc)) va don vi ((cua tre) OR (cua triet))*.