Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
dang xay » dang van, van xay
nang xa » nang x, lang xa, nang ma
hanh ve » hanh vi, hanh va, hanh kem
hieu ve » hieu va, hieu van
hoc cac » hoc cao
te sac » te sach, te cac, te san
sac ky » cac ky, sai ky
ve cac » va cac, vien cac
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: te sac ky ((nang xa) or (dang xay)) hoi. hieu ve cac ((duc tan) or (hoc cac)) hanh ve su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky ((nang xa) OR (dang xay)) hoi. hieu ve cac ((duc tan) OR (hoc cac)) hanh ve su triet.
• Adding a wildcard symbol may retrieve word variants: te sac ky ((nang xa) or (dang xay)) hoi. hieu ve cac ((duc tan) or (hoc cac)) hanh ve su triet*.