Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
tham luc » than luc, tham nuoc, tham thuc
nang xa » nang x, lang xa, mang xa
cua tre » cua te, cuu tre, dua tren
dinh vi » dinh ve, dinh viet, dinh tri
va dinh » van dinh, va kinh, va tinh
va tham » van tham, va cham, va thanh
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
luc va » duc va, tuc va, loc va
tu van » tu va

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu van ky ((nang xa) OR (nang ma)) hoi. hieu va tham luc va dinh vi ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu van ky ((nang xa) OR (nang ma)) hoi. hieu va tham luc va dinh vi ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu van ky ((nang xa) OR (nang ma)) hoi. hieu va tham luc va dinh vi ((cua tre) or (cua triet))".
• Adding a wildcard symbol may retrieve word variants: tu van ky ((nang xa) OR (nang ma)) hoi. hieu va tham luc va dinh vi ((cua tre) or (cua triet))*.