Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
te sach » toc sach
lua tre » cua tre, dua tren, luat tri
doan vi » doan va, don vi, doan thi
va doan » va doanh, van doan, va dan
cac luc » cau luc, coc luc, cac nuoc
hieu ve » hieu va
luy tre » luyen tre
y nang » ky nang, ly nang, v nang
luc va » duc va, tuc va, loc va
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach y nang x hoi. ((hieu ve) OR (hieu van)) cac luc va doan vi ((lua tre) or (luy tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y nang x hoi. ((hieu ve) OR (hieu van)) cac luc va doan vi ((lua tre) OR (luy tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y nang x hoi. ((hieu ve) OR (hieu van)) cac luc va doan vi ((lua tre) or (luy tre))".
• Adding a wildcard symbol may retrieve word variants: te sach y nang x hoi. ((hieu ve) OR (hieu van)) cac luc va doan vi ((lua tre) or (luy tre))*.