Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh di » thanh doi, thanh de, thanh do
thuc ban » thuoc ban, thuc dan, thu ban
nam thuc » nam thuoc, am thuc, nam thu
so viet » hoc viet
hieu ve » hieu va, hieu van
hoc hoi » hoc khoi, hoc hoa, hoc noi
ky dang » ky nang, ky danh
sac ky » cac ky, sai ky
ve nam » he nam, va nam, le nam
ho hoi » hoa hoi, hoi hoi, co hoi
su sac » su sach, su cac, su xac

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 dang ((ho hoi) OR (hoc hoi)). hieu ve nam thuc ban thanh di ((va thiet) or (so viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky dang ((ho hoi) OR (hoc hoi)). hieu ve nam thuc ban thanh di ((va thiet) OR (so viet))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sac ky dang ((ho hoi) OR (hoc hoi)). hieu ve nam thuc ban thanh di ((va thiet) or (so viet))*".