Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
su triet » su viet, su tien, ve triet
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
va hanh » va thanh, va danh, ban hanh
y nang » ky nang, ly nang, v nang
ve cam » ve cham, ve cac, va cam
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: toc sach y nang ((xa hoi) OR (mai hoi)). hieu ve cam xuc ((va hanh) OR (van hanh)) vi su triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y nang ((xa hoi) or (mai hoi)). hieu ve cam xuc ((va hanh) OR (van hanh)) vi su triet~".
• Adding a wildcard symbol may retrieve word variants: toc sach y nang ((xa hoi) or (mai hoi)). hieu ve cam xuc ((va hanh) OR (van hanh)) vi su triet*.