Perhaps you should try some spelling variations:
ban hanh » ban hang
nam thuc » nam thuoc, am thuc, nam thu
co viet » so viet, o viet, hoc viet
ky danh » ky anh, ky dang
va danh » va dinh, va dan, va hanh
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
su sac » su sach, su cac, su xac
sac ky » cac ky, sai ky
ma hoi » xa hoi, ma hoa, me hoi
ve nam » he nam, va nam, le nam
di co » doi co, de co, xi co

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sac ky danh ((ma hoi) or (mai hoi)). hieu ve nam thuc ((ban hanh) or (va danh)) di co viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky danh ((ma hoi) OR (mai hoi)). hieu ve nam thuc ((ban hanh) OR (va danh)) di co viet.
• Adding a wildcard symbol may retrieve word variants: su sac ky danh ((ma hoi) or (mai hoi)). hieu ve nam thuc ((ban hanh) or (va danh)) di co viet*.