Perhaps you should try some spelling variations:
cua triet » cua viet, va triet
thanh lam » thanh lap, hanh lam, thanh nam
su triet » su viet, su tien, ve triet
va thanh » gia thanh, ban thanh, va tinh
cac duc » cac du, cao duc, cac dac
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
ky dang » ky nang, ky danh
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky dang ((xa hoi) or (ha noi)). hieu ve cac duc va thanh lam ((cua triet) OR (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky dang ((xa hoi) OR (ha noi)). hieu ve cac duc va thanh lam ((cua triet) OR (su triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky dang ((xa hoi) or (ha noi)). hieu ve cac duc va thanh lam ((cua triet) OR (su triet))".
• Adding a wildcard symbol may retrieve word variants: su sach ky dang ((xa hoi) or (ha noi)). hieu ve cac duc va thanh lam ((cua triet) OR (su triet))*.