Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van pham » san pham, van phan, van phat
van hanh » van thanh, ban hanh, van anh
su triet » su viet, su tien, ve triet
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
tang ma » tang van
duc van » duc va, duc tan, duc manh
vi su » va su, ve su, ki su

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: tu sach y ((nang xa) OR (((tang ma) OR (mang may)))) hoi. hieu van pham duc van hanh vi su triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((nang xa) or (((tang ma) OR (mang may)))) hoi. hieu van pham duc van hanh vi su triet~".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang xa) or (((tang ma) OR (mang may)))) hoi. hieu van pham duc van hanh vi su triet*.