Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
sach ky » sach y, sach ty, sach kem
hieu ve » hieu va, hieu van
cao duc » dao duc, cao suc, giao duc
va hanh » van hanh, va thanh, va danh
sac ky » cac ky, sai ky
ve cao » va cao, ve bao, ve cac
cua te » cua tu
x hoi » xa hoi, o hoi, x ho

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

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