Perhaps you should try some spelling variations:
cua triet » cua viet, va triet
su triet » su viet, su tien, ve triet
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
ly vang » ly hang, ly van, ly quang
ly nang » ky nang, ly hang, ly quang
hieu ve » hieu va, hieu van
ve ban » te ban, va ban, ve bao
ban bo » can bo, ban do, ban co
bo van » vo van, so van, do van
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: tu sach ((ly nang) OR (ly vang)) x hoi. hieu ve ban bo van hanh vi ((cua triet) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ly nang) OR (ly vang)) x hoi. hieu ve ban bo van hanh vi ((cua triet) OR (su triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ly nang) OR (ly vang)) x hoi. hieu ve ban bo van hanh vi ((cua triet) or (su triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ly nang) OR (ly vang)) x hoi. hieu ve ban bo van hanh vi ((cua triet) or (su triet))*.