Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
su triet » su viet, su tien, ve triet
so sach » so sanh, bo sach, co sach
ty nang » ky nang, ty xang, ly nang
ty hang » ly hang, ty xang, thi hang
hieu ke » hieu kem, chieu ke, hieu ky
ke phan » ve phan, kenh phan, ke thang
va hanh » van hanh, va thanh, va danh
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 nang) OR (ty hang)) xa hoi. hieu ke phan tu ((va hanh) or (ban thanh)) vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((ty nang) OR (ty hang)) xa hoi. hieu ke phan tu ((va hanh) OR (ban thanh)) vi su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ((ty nang) OR (ty hang)) xa hoi. hieu ke phan tu ((va hanh) or (ban thanh)) vi su triet".
• Adding a wildcard symbol may retrieve word variants: so sach ((ty nang) OR (ty hang)) xa hoi. hieu ke phan tu ((va hanh) or (ban thanh)) vi su triet*.