Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
dinh lap » dinh lam, trinh lap, dinh lang
lap cua » lai cua, tap cua, lam cua
thu nam » tu nam, thu nhap, thu nhat
hieu he » hieu ve, hiem he, hieu le
tu sach » thu sach, te sach, tu cach
nang ma » sang ma, nang cao, mang may
su sach » so sach, vu sach
tang ma » mang may, tang van
he nam » ha nam, nghe nam

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 ma) OR (tang ma)) hoi. hieu he nam thu nam dinh lap cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky ((nang ma) OR (tang ma)) hoi. hieu he nam thu nam dinh lap cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) ky ((nang ma) OR (tang ma)) hoi. hieu he nam thu nam dinh lap cua triet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky ((nang ma) OR (tang ma)) hoi. hieu he nam thu nam dinh lap cua triet*.