Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
dang xay » dang van, van xay
hoc cac » hoc cao
hieu ve » hieu va, hieu van
lang xa » lang ha, lang van
sac ky » cac ky, sai ky
ve cac » va cac, vien cac
te sac » te sach, te cac, te san
vi su » va su, ve su, ki su

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sac ky ((lang xa) or (dang xay)) hoi. hieu ve cac ((duc tan) or (hoc cac)) hanh vi su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky ((lang xa) OR (dang xay)) hoi. hieu ve cac ((duc tan) OR (hoc cac)) hanh vi su triet.
• Adding a wildcard symbol may retrieve word variants: te sac ky ((lang xa) or (dang xay)) hoi. hieu ve cac ((duc tan) or (hoc cac)) hanh vi su triet*.