Perhaps you should try some spelling variations:
cua triet » su triet, va triet
cua viet » ca viet, hoa viet, cua vat
van doan » van doanh, van toan, van hoan
hieu van » hieu va, thien van, lieu va
lang xa » lang ha, dang xay, lang van
sach ty » sach y, sach tu, sach thu
van cam » van nam, van lam, van cau
nang xa » nang x, nang ma, mang xa
tu sach » thu sach, su sach, te sach
cam so » nam so, ham so, cam lo
so van » su van, vo van

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