Perhaps you should try some spelling variations:
nhan thuc » nhan luc, dan thuc, toan thuc
nham thuc » nam thuc, nham thu, pham thuc
sang mai » sang ma, sang tai, lang mai
cham tuc » pham thuc, tham thuc, cham soc
cua tre » cua te, cuu tre, cua triet
ky sang » ky nang, ky dang, ky tang
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
vi cua » vai cua, di cua
va don » va dong, va doc, va do
tu sac » tu sach, tu cac, tu san
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) OR (nhan thuc)))) va don vi cua tre~.
• 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) OR (nhan thuc)))) va don vi cua tre.
• 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) OR (nhan thuc)))) va don vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sac ky sang mai hoi. hieu ve ((cham tuc) or (((nham thuc) OR (nhan thuc)))) va don vi cua tre*.