Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
ve triet » va trien, su triet
hoc sac » hoc sach, hoc cac, hoc mac
cao hoi » cau hoi, co hoi, cao hoc
van cau » van dau, van hau, van chat
sac ky » cac ky, sai ky
tuc va » thuc va, truc va, duc va
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sac ky nang cao hoi. hieu van cau ((tuc va) OR (tuc xa)) hanh vi ((cua tu) or (ve triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sac ky nang cao hoi. hieu van cau ((tuc va) OR (tuc xa)) hanh vi ((cua tu) OR (ve triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sac ky nang cao hoi. hieu van cau ((tuc va) OR (tuc xa)) hanh vi ((cua tu) or (ve triet))".
• Adding a wildcard symbol may retrieve word variants: hoc sac ky nang cao hoi. hieu van cau ((tuc va) OR (tuc xa)) hanh vi ((cua tu) or (ve triet))*.