Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
bach van » bach dan, cach van, bach dang
tan hanh » tan thanh, tang hanh, toan hanh
sach van » sach han, sach va, cach van
hanh ki » hanh vi, hanh ky, hanh kien
cac duc » cac du, cao duc, cac dac
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
x hoi » xa hoi, x ho, 5 hoi
ki su » ky su
o hoi » co hoi, o hoc, o hai

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 van) OR (bach van)) nang ((x hoi) or (o hoi)). hieu ve cac duc tan hanh ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach van) OR (bach van)) nang ((x hoi) OR (o hoi)). hieu ve cac duc tan hanh ki su triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach van) OR (bach van)) nang ((x hoi) or (o hoi)). hieu ve cac duc tan hanh ki su triet*".