Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
thanh ve » hanh ve, thanh va, thanh vien
xa thanh » va thanh, ha thanh, ta thanh
cac tac » cac toc, cac bac, cac dac
hieu va » lieu va, hieu qua
hieu ve » hieu van
tu sach » thu sach, te sach, tu cach
xang co » nang co, lang co, tang co
su sach » so sach, vu sach
co hai » co dai, co hoi, o hai
tac xa » tuc xa, tac da
ve su » va su

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