Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
thanh di » thanh doi, thanh de, thanh do
cac lop » cac hop, cac loai
cac loc » cac toc, cac hoc, cac nuoc
nang xa » lang xa, nang ma, mang xa
san ky » sang ky, van ky, dan ky
di cua » dai cua, doi cua, de cua
tu san » thu san, tu ban, tu can

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu san ky ((nang xa) OR (nang x)) hoi. hieu van ((cac loc) or (cac lop)) gia thanh di cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu san ky ((nang xa) OR (nang x)) hoi. hieu van ((cac loc) OR (cac lop)) gia thanh di cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu san ky ((nang xa) OR (nang x)) hoi. hieu van ((cac loc) or (cac lop)) gia thanh di cua triet".
• Adding a wildcard symbol may retrieve word variants: tu san ky ((nang xa) OR (nang x)) hoi. hieu van ((cac loc) or (cac lop)) gia thanh di cua triet*.