Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
cau treo » cau theo, cau tren, cau triet
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang xa » lang xa, nang ma, mang xa
hieu ve » hieu va, hieu van
cac duc » cac du, cao duc, cac dac
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
ve cac » va cac, vien 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 ky ((nang xa) OR (nang x)) hoi. hieu ve cac duc va hanh di ((cau treo) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (nang x)) hoi. hieu ve cac duc va hanh di ((cau treo) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang xa) OR (nang x)) hoi. hieu ve cac duc va hanh di ((cau treo) or (cua triet))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang xa) OR (nang x)) hoi. hieu ve cac duc va hanh di ((cau treo) or (cua triet))*.