Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
cac truc » cau truc, cac tru, cac trung
thanh va » thanh van, hanh va, thanh ha
thanh vi » hanh vi, thanh ve, nhanh vi
truc va » thuc va, thuc vat, trung va
so sach » bo sach, co sach, hoc sach
hieu ve » hieu va, hieu van
so sanh » do sanh
xang o » lang o, tang o, dang o
ve cac » va cac, vien cac
o hoc » co hoc, mo hoc, so hoc

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sach) or (so sanh)) ty xang o hoc. hieu ve cac truc va ((thanh vi) OR (thanh va)) su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (so sanh)) ty xang o hoc. hieu ve cac truc va ((thanh vi) OR (thanh va)) su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sach) or (so sanh)) ty xang o hoc. hieu ve cac truc va ((thanh vi) OR (thanh va)) su triet".
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (so sanh)) ty xang o hoc. hieu ve cac truc va ((thanh vi) OR (thanh va)) su triet*.