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