Perhaps you should try some spelling variations:
ve triet » va trien
su triet » su viet, su tien
thanh vi » hanh vi, thanh va, thanh ve
xa thanh » va thanh, ha thanh, ta thanh
cac tuc » cac toc, cac tu, cac tac
sach ty » sach y, sach tu, sach thu
tu sach » thu sach, su sach, te sach
ty nang » ky nang, ty xang, ty hang
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
o hoc » co hoc, mo hoc, so hoc
o hoi » co hoi, o hai, o hoa

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 nang ((o hoi) OR (o hoc)). hieu ve cac tuc xa thanh vi ((su triet) or (ve triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((o hoi) OR (o hoc)). hieu ve cac tuc xa thanh vi ((su triet) OR (ve triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang ((o hoi) OR (o hoc)). hieu ve cac tuc xa thanh vi ((su triet) or (ve triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((o hoi) OR (o hoc)). hieu ve cac tuc xa thanh vi ((su triet) or (ve triet))*.