Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
vat thanh » dat thanh, gat thanh, tat thanh
qua pham » quan pham, quy pham, qua cham
pham duy » pham duc
thanh di » thanh doi, thanh de, thanh do
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
di cua » dai cua, doi cua, de cua
o hoi » co hoi, o hoc, o hoa
o hai » co hai, so hai, o lai

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) OR (o hai)). hieu qua pham duy vat thanh di cua triet~.
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((o hoi) or (o hai)). hieu qua pham duy vat thanh di cua triet*.