Perhaps you should try some spelling variations:
vanh tai » van tai, hanh tai, anh tai
su triet » su viet, su tien, ve triet
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
qua cac » cua cac
co hoi » co loi
xuc va » tuc va, luc va, xac va
tai su » tai so, tai tu, lai 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: su sach ky nang ((co hoi) OR (co hoc)). hieu qua cac ((xuc va) OR (duc va)) vanh tai su triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((co hoi) OR (co hoc)). hieu qua cac ((xuc va) or (duc va)) vanh tai su triet~".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((co hoi) OR (co hoc)). hieu qua cac ((xuc va) or (duc va)) vanh tai su triet*.