Perhaps you should try some spelling variations:
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
su triet » su viet, su tien, ve triet
so sach » so sanh, bo sach, co sach
sach ty » sach y, sach tu, sach thu
ty lang » tay lang, ty xang, ty hang
lang xa » lang ha, dang xay, lang van
hieu ke » hieu kem, chieu ke, hieu ky
ke phan » ve phan, kenh phan, ke thang
va tinh » may tinh
vi su » va su, ve su, ki su

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ty lang xa hoi. hieu ke phan tu ((((ban hanh) or (van hanh))) or (va tinh)) vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty lang xa hoi. hieu ke phan tu ((((ban hanh) OR (van hanh))) OR (va tinh)) vi su triet.
• Adding a wildcard symbol may retrieve word variants: so sach ty lang xa hoi. hieu ke phan tu ((((ban hanh) or (van hanh))) or (va tinh)) vi su triet*.