Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
day thanh » dao thanh, dat thanh, da thanh
hieu van » hieu va, thien van, lieu va
thanh ve » hanh ve, thanh va, thanh vien
thuc day » thuc dan, thuc vat
van cham » van chat, van tham, va cham
cua tre » cuu tre, cua triet, dua tren
ky sang » ky nang, ky dang, ky tang
sang ma » tang ma, nang ma, sang tao
tu cai » tu cac, tu can, tu cay
ma hoi » mai hoi, xa hoi, ma hoa
tu bai » tu ban, tu bat, te bai
cua te » cua tu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cai) OR (tu bai)) ky sang ma hoi. hieu van cham thuc day thanh ve ((cua tre) OR (cua te))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu cai) or (tu bai)) ky sang ma hoi. hieu van cham thuc day thanh ve ((cua tre) OR (cua te))~".
• Adding a wildcard symbol may retrieve word variants: ((tu cai) or (tu bai)) ky sang ma hoi. hieu van cham thuc day thanh ve ((cua tre) OR (cua te))*.