Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
thanh vi » hanh vi, thanh va, thanh ve
xa thanh » va thanh, ha thanh, ta thanh
hieu van » hieu va, thien van, lieu va
sach ty » sach tu, sach thu, xach tay
cac tac » cac toc, cac bac, cac dac
hieu ve » hieu va
nang o » nang co, nang ho, nang ro
tac xa » tuc xa, tac da
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 ty) or (sach y)) nang o hoi. ((hieu ve) OR (hieu van)) cac tac xa thanh vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sach y)) nang o hoi. ((hieu ve) OR (hieu van)) cac tac xa thanh vi su triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ty) or (sach y)) nang o hoi. ((hieu ve) OR (hieu van)) cac tac xa thanh vi su triet*".