Perhaps you should try some spelling variations:
cua triet » cua viet, su triet
va triet » va thiet, va trien, ve triet
thanh do » thanh de, thanh pho, thanh hoa
duy can » duy van
tu sach » thu sach, su sach, te sach
sach tu » sach thu, cach tu, sach ty
duy ban » uy ban, duy van, dua ban
va pham » van pham, va phat, va phap
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
tu nang » tru nang, tu nong, tu nano

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