Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
nang doc » nang luc
cac tac » cac toc, cac bac, cac dac
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
tu sach » thu sach, su sach, te sach
lang ha » long ha
lang xa » dang xay, lang van
tac xa » tuc xa, tac da
ve cac » va cac, vien cac

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 ky ((lang xa) OR (lang ha)) hoi. hieu ve cac tac xa ((nang noi) or (nang doc)) va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((lang xa) OR (lang ha)) hoi. hieu ve cac tac xa ((nang noi) OR (nang doc)) va triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((lang xa) OR (lang ha)) hoi. hieu ve cac tac xa ((nang noi) or (nang doc)) va triet*".