Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
cau tren » cu tren, dau tren, ca tren
tu sach » thu sach, su sach, te sach
ty nang » ty xang, ty hang, ly nang
hieu ve » hieu va, hieu van
cao duc » dao duc, cao suc, giao duc
va hanh » van hanh, va thanh, va danh
ve cao » va cao, ve bao, ve cac

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