Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
van hanh » van thanh, ban hanh, van anh
va danh » va dinh, va dan, va hanh
hieu va » lieu va, hieu qua
su sach » so sach, vu sach
nang ma » tang ma, sang ma, mang may
sach v » sach va, sach y, sach 2
va tai » va tac, va tap
vi va » vi van, vai va, vu va

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