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 tien, ve triet
tu sach » thu sach, su sach, te sach
lang xa » lang ha, dang xay, lang van
duc van » duc va, duc tan, duc manh
su viet » so viet

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