Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
te sach » toc sach
van cac » van hac, van cau, van bac
va doan » va doanh, van doan, va dan
doan vi » doan va, don vi, doan thi
lua tre » cua tre, luy tre, dua tren
y nang » ky nang, ly nang, v nang
vi lua » vi luu
x hoi » xa hoi, x ho
o hoi » co hoi, o hoc, o hai

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) OR (5 hoi))) or (o hoi)). hieu van cac nuoc va doan vi lua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y nang ((((x hoi) OR (5 hoi))) OR (o hoi)). hieu van cac nuoc va doan vi lua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y nang ((((x hoi) OR (5 hoi))) or (o hoi)). hieu van cac nuoc va doan vi lua tre".
• Adding a wildcard symbol may retrieve word variants: te sach y nang ((((x hoi) OR (5 hoi))) or (o hoi)). hieu van cac nuoc va doan vi lua tre*.