Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
dac trung » duc trung, cac truong, tai trung
cac trung » cac truong, bac trung, cao trung
va hanh » van hanh, va thanh, va danh
so sach » so sanh, bo sach, co sach
mai hoi » mai khoi, dai hoi, lai hoi
sach 2 » sach y
ma hoi » xa hoi, ma hoa, me hoi
2 nang » v nang
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach 2 nang ((ma hoi) OR (mai hoi)). hieu qua ((cac trung) or (dac trung)) va hanh vi cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach 2 nang ((ma hoi) OR (mai hoi)). hieu qua ((cac trung) OR (dac trung)) va hanh vi cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach 2 nang ((ma hoi) OR (mai hoi)). hieu qua ((cac trung) or (dac trung)) va hanh vi cua triet".
• Adding a wildcard symbol may retrieve word variants: so sach 2 nang ((ma hoi) OR (mai hoi)). hieu qua ((cac trung) or (dac trung)) va hanh vi cua triet*.