Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
thanh ve » hanh ve, thanh va, thanh vien
thanh vi » hanh vi, thanh va, nhanh vi
cac dac » cac dan, cac dai, cac bac
sach ty » sach y, sach thu, xach tay
hieu ve » hieu va, hieu van
sach tu » sach thu, cach tu, sach uu
xang o » lang o, tang o, dang o
dac xa » tac xa, cac xa, dan xa
ve cac » va cac, vien cac
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 ty) or (sach tu)) xang o hoi. hieu ve cac dac xa ((thanh vi) OR (thanh ve)) su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sach tu)) xang o hoi. hieu ve cac dac xa ((thanh vi) OR (thanh ve)) su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ty) or (sach tu)) xang o hoi. hieu ve cac dac xa ((thanh vi) OR (thanh ve)) su triet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) or (sach tu)) xang o hoi. hieu ve cac dac xa ((thanh vi) OR (thanh ve)) su triet*.