Perhaps you should try some spelling variations:
dang xay » dang van, van xay
van hanh » van thanh, ban hanh, van anh
va triet » va thiet, va trien, ve triet
su sach » so sach, vu sach
lang xa » lang ha, lang van
hieu ke » hieu kem, chieu ke, hieu ky
cau duc » cao duc, cau luc, chu duc
va hanh » va thanh, va danh, ban hanh
ke cau » ket cau

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y ((lang xa) OR (dang xay)) hoi. hieu ke cau duc ((va hanh) or (van hanh)) tu va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((lang xa) OR (dang xay)) hoi. hieu ke cau duc ((va hanh) OR (van hanh)) tu va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((lang xa) OR (dang xay)) hoi. hieu ke cau duc ((va hanh) or (van hanh)) tu va triet".
• Adding a wildcard symbol may retrieve word variants: su sach y ((lang xa) OR (dang xay)) hoi. hieu ke cau duc ((va hanh) or (van hanh)) tu va triet*.