Perhaps you should try some spelling variations:
su sach » so sach, vu sach
hanh va » hang va, hanh vi
va hanh » van hanh, va thanh, va danh
ve chat » va chat, van chat
sach ly » sach y, sach lo, sach ty
va cham » va chat, va tham
ly hang » ly quang
su viet » so viet
ca hoi » cau hoi, cua hoi, co hoi
loc va » hoc va, luc va

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 ly hang ((ca hoi) OR (xa hoi)). hieu ((va cham) or (ve chat)) loc va hanh va su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ly hang ((ca hoi) OR (xa hoi)). hieu ((va cham) OR (ve chat)) loc va hanh va su viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ly hang ((ca hoi) OR (xa hoi)). hieu ((va cham) or (ve chat)) loc va hanh va su viet".
• Adding a wildcard symbol may retrieve word variants: su sach ly hang ((ca hoi) OR (xa hoi)). hieu ((va cham) or (ve chat)) loc va hanh va su viet*.