Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
cao hoa » cao hoat, cao khoa, cau hoa
hieu va » lieu va, hieu qua
cac tac » cac toc, cac bac, cac dac
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, dua tren
tac va » tac da, tac xa, tuc va

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