Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
cua viet » ca viet, hoa viet, cua vat
tao khoi » tao hoi, thao khoa, tao boi
lao khoa » lo khoa, da khoa, ly khoa
va danh » va dinh, va dan, dia danh
hieu le » hieu ve, hieu he, hieu ly
ky sang » ky nang, ky dang, ky tang
va hanh » van hanh, va thanh, ban hanh
di cua » dai cua, doi cua, de cua
su cao » cu cao, vu cao, su co
le nam » ly nam, he nam, le na

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

• Performing a fuzzy search may retrieve terms with similar spellings: su cao ky sang ((tao khoi) OR (lao khoa)). hieu le nam thuoc ((va hanh) or (va danh)) di cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su cao ky sang ((tao khoi) OR (lao khoa)). hieu le nam thuoc ((va hanh) OR (va danh)) di cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su cao ky sang ((tao khoi) OR (lao khoa)). hieu le nam thuoc ((va hanh) or (va danh)) di cua viet".
• Adding a wildcard symbol may retrieve word variants: su cao ky sang ((tao khoi) OR (lao khoa)). hieu le nam thuoc ((va hanh) or (va danh)) di cua viet*.