Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
duc ban » duc tan, dua ban, duc man
qua ban » cua ban, qua quan
duc van » duc va, duc tan, duc manh
tu sach » thu sach, su sach, te sach
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
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: tu sach v nang o hoi. hieu ve cac ((((duc ban) OR (duc van))) or (qua ban)) hanh vi su triet~.
• 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 (duc van))) OR (qua ban)) hanh vi su triet*.
• 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 (duc van))) or (qua ban)) hanh vi su triet*".