Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
va pham » van pham, va phat, va phap
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, dua tren

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