Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
hieu van » hieu va, thien van, lieu va
hanh ki » hanh vi, hanh ky, hanh kien
can ban » van ban, toan ban
cam ban » cac ban, cam bay, lam ban
thu sac » thu sach, thu san, thu xac
van cac » van hac, van cau, van bac
nang xa » nang x, lang xa, nang ma
sac ky » cac ky, sai ky
ki su » ky su

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sac ky ((nang xa) or (trong cac)) hoi. hieu van cac ((cam ban) OR (can ban)) hanh ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sac ky ((nang xa) OR (trong cac)) hoi. hieu van cac ((cam ban) OR (can ban)) hanh ki su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sac ky ((nang xa) or (trong cac)) hoi. hieu van cac ((cam ban) OR (can ban)) hanh ki su triet".
• Adding a wildcard symbol may retrieve word variants: thu sac ky ((nang xa) or (trong cac)) hoi. hieu van cac ((cam ban) OR (can ban)) hanh ki su triet*.