Perhaps you should try some spelling variations:
te sach » toc sach
cac luc » cau luc, coc luc, cac nuoc
cua tre » cua te, cuu tre, cua triet
doan vi » don vi, doan thi, doan van
sach lo » sach dao, sach doi, sach hoi
hieu ve » hieu va, hieu van
lo nang » ho nang, ly nang, loai nang
luy tre » luyen tre
ve cac » va cac, vien cac
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 lo nang x hoi. hieu ve cac luc va ((doan vi) OR (doan va)) ((cua tre) or (luy tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach lo nang x hoi. hieu ve cac luc va ((doan vi) OR (doan va)) ((cua tre) OR (luy tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach lo nang x hoi. hieu ve cac luc va ((doan vi) OR (doan va)) ((cua tre) or (luy tre))".
• Adding a wildcard symbol may retrieve word variants: te sach lo nang x hoi. hieu ve cac luc va ((doan vi) OR (doan va)) ((cua tre) or (luy tre))*.