Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
ban hang » ngan hang
cua viet » ca viet, hoa viet, cua dieu
may thoi » gay thoi, may thi, tay thoi
hang vai » hang va, hang tai, hang hai
thuc ban » thuoc ban, thuc dan, thu ban
hieu va » lieu va, hieu qua
ky mang » ky nang, ke mang, ky dang
may hoi » tay hoi, mai hoi, may hmi
va tham » van tham, va cham, va thanh
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) or (may thoi)). hieu va tham thuc ban hang vai ((cua viet) OR (cua vat))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky mang ((may hoi) OR (may thoi)). hieu va tham thuc ban hang vai ((cua viet) OR (cua vat)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky mang ((may hoi) or (may thoi)). hieu va tham thuc ban hang vai ((cua viet) OR (cua vat))".
• Adding a wildcard symbol may retrieve word variants: tu sac ky mang ((may hoi) or (may thoi)). hieu va tham thuc ban hang vai ((cua viet) OR (cua vat))*.