Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
thanh de » hanh de, thanh ve, thanh do
thanh di » thanh doi, thanh do, thanh dinh
pham duy » pham duc
sach tu » sach thu, cach tu, sach ty
duy van » duy vat, dung van
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
tu nang » tru nang, tu nong, tu nano
ve pham » vi pham, v pham, ve phan
o hai » co hai, so hai, o lai
o hoi » co hoi, o hoc, o hoa

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 tu nang ((o hoi) OR (o hai)). hieu ve pham duy van ((thanh di) OR (thanh de)) su triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach tu nang ((o hoi) OR (o hai)). hieu ve pham duy van ((thanh di) or (thanh de)) su triet~".
• Adding a wildcard symbol may retrieve word variants: tu sach tu nang ((o hoi) OR (o hai)). hieu ve pham duy van ((thanh di) or (thanh de)) su triet*.