Perhaps you should try some spelling variations:
su triet » su viet, ve triet
tu sach » thu sach, su sach, te sach
qua ban » cua ban, qua quan
duc ban » duc tan, duc van, dua ban
su tien » su kien, su hien, tu tieng
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
sach v » sach va, sach y, sach 2
nang o » nang co, nang ho, nang ro
v nang » va nang, vu nang, van nang
o hoi » co hoi, o hoc, o hai

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: tu sach v nang o hoi. hieu ve cac ((duc ban) OR (qua ban)) hanh vi ((su triet) OR (su tien))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach v nang o hoi. hieu ve cac ((duc ban) or (qua ban)) hanh vi ((su triet) OR (su tien))~".
• Adding a wildcard symbol may retrieve word variants: tu sach v nang o hoi. hieu ve cac ((duc ban) or (qua ban)) hanh vi ((su triet) OR (su tien))*.