Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
lam duoc » nam duoc, luat duoc, lam thuoc
va hanh » va thanh, va danh, ban hanh
tu sach » thu sach, su sach, te sach
nang ma » sang ma, nang cao, mang may
tang ma » mang may, tang van
van lam » van nam
de cua » le cua, te cua, dieu cua

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