Perhaps you should try some spelling variations:
ve triet » va trien
hieu van » hieu va, thien van, lieu va
su triet » su viet, su tien
thanh va » thanh van, hanh va, thanh ha
thanh vi » hanh vi, thanh ve, nhanh vi
van cac » van hac, van cau, van bac
cac tuc » cac toc, cac tu, cac tac
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
tu sach » thu sach, su sach, te sach
nang o » nang co, nang ho, nang ro
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 ty nang o hoi. hieu van cac tuc xa ((thanh vi) OR (thanh va)) ((su triet) OR (ve triet))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang o hoi. hieu van cac tuc xa ((thanh vi) OR (thanh va)) ((su triet) or (ve triet))~".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang o hoi. hieu van cac tuc xa ((thanh vi) OR (thanh va)) ((su triet) or (ve triet))*.