Perhaps you should try some spelling variations:
ve triet » va trien, su triet
van hanh » van thanh, ban hanh, van anh
cac truc » cau truc, cac tru, cac trung
va hanh » va thanh, va danh, ban hanh
so sach » so sanh, bo sach, co sach
nang ma » sang ma, nang cao, mang may
tang ma » mang may, tang van
hieu ve » hieu va, hieu van
sach v » sach va, sach y, sach 2
ve cac » va cac, vien cac
vi ve » va ve, gi ve, ve ve

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: so sach v ((nang ma) OR (tang ma)) hoi. hieu ve cac truc ((va hanh) OR (van hanh)) vi ve triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach v ((nang ma) OR (tang ma)) hoi. hieu ve cac truc ((va hanh) or (van hanh)) vi ve triet~".
• Adding a wildcard symbol may retrieve word variants: so sach v ((nang ma) OR (tang ma)) hoi. hieu ve cac truc ((va hanh) or (van hanh)) vi ve triet*.