Perhaps you should try some spelling variations:
su triet » su viet, ve triet
thanh vi » hanh vi, thanh va, thanh ve
xa thanh » va thanh, ha thanh, ta thanh
te sach » toc sach
cac tuc » cac toc, cac tu, cac tac
su tien » su kien, su hien, tu tieng
ty nang » ky nang, ty hang, ly nang
hieu ve » hieu va, hieu van
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: te sach ((ty nang) or (ty xang)) o hoi. hieu ve cac tuc xa thanh vi ((su triet) OR (su tien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((ty nang) OR (ty xang)) o hoi. hieu ve cac tuc xa thanh vi ((su triet) OR (su tien)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((ty nang) or (ty xang)) o hoi. hieu ve cac tuc xa thanh vi ((su triet) OR (su tien))".
• Adding a wildcard symbol may retrieve word variants: te sach ((ty nang) or (ty xang)) o hoi. hieu ve cac tuc xa thanh vi ((su triet) OR (su tien))*.