Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
thuc ban » thuoc ban, thuc dan, thu ban
ban hanh » ban hang
hanh tai » thanh tai, hang tai, han tai
cua viet » ca viet, hoa viet, cua vat
ky mang » ky nang, ke mang, ky dang
may hoi » may thoi, tay hoi, mai hoi
hieu va » hieu qua
tai cua » thai cua, tai cuc, tri cua
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 mang may hoi. ((hieu va) or (lieu va)) tham thuc ban hanh tai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky mang may hoi. ((hieu va) OR (lieu va)) tham thuc ban hanh tai cua viet.
• Adding a wildcard symbol may retrieve word variants: tu sac ky mang may hoi. ((hieu va) or (lieu va)) tham thuc ban hanh tai cua viet*.