Perhaps you should try some spelling variations:
thanh vinh » thanh binh, thanh tinh, thanh van
hieu cua » hieu qua, dieu cua, bieu cua
va triet » va thiet, va trien, ve triet
tu sach » thu sach, su sach, te sach
cua nam » cua tam, cua ngan, cua nhan
cua gia » cua giao, qua gia
y nang » ky nang, ly nang, v nang
co hoi » co hoc, co loi
o hoi » o hoc, o hai, o hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y nang ((o hoi) OR (co hoi)). hieu cua nam cua gia ((thanh vinh) or (than kinh)) va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ((o hoi) OR (co hoi)). hieu cua nam cua gia ((thanh vinh) OR (than kinh)) va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang ((o hoi) OR (co hoi)). hieu cua nam cua gia ((thanh vinh) or (than kinh)) va triet".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ((o hoi) OR (co hoi)). hieu cua nam cua gia ((thanh vinh) or (than kinh)) va triet*.