Perhaps you should try some spelling variations:
cua triet » cua viet, su triet
va triet » va thiet, va trien, ve triet
va hanh » van hanh, va thanh, va danh
hanh va » hang va, hanh vi
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
hai tuc » thai tuc, hai cuc, thai thuc
va hai » van hai, va chai, va khai
tuc va » thuc va, truc va, tuc xa

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