Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
mai hoi » mai khoi, dai hoi, lai hoi
sach ky » sac ky, sach y, sach ty
van cau » van dau, van hau, van chat
hanh di » hanh vi, hanh de, hang di
su sach » so sach, vu sach
ma hoi » xa hoi, ma hoa, me hoi
luc va » tuc va, loc va
di cua » dai cua, doi cua, de cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((ma hoi) OR (mai hoi)). hieu van cau ((luc va) OR (duc va)) hanh di cua triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((ma hoi) or (mai hoi)). hieu van cau ((luc va) OR (duc va)) hanh di cua triet~".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((ma hoi) or (mai hoi)). hieu van cau ((luc va) OR (duc va)) hanh di cua triet*.