Perhaps you should try some spelling variations:
te sach » toc sach
hanh va » hang va
luc van » luoc van, luu van, duc van
cao luc » bao luc, cao duc, cao suc
su tien » su kien, su hien, tu tieng
sach vu » sach va, sach tu, sach uu
hieu va » lieu va
dang ha » dong ha, dung ha, lang ha
vu dang » su dang, vu quang, cua dang
ha hoi » hoa hoi, ha noi, xa hoi

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 vu dang ha hoi. ((hieu va) OR (hieu qua)) cao luc van ((hanh va) or (hanh vi)) su tien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach vu dang ha hoi. ((hieu va) OR (hieu qua)) cao luc van ((hanh va) OR (hanh vi)) su tien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach vu dang ha hoi. ((hieu va) OR (hieu qua)) cao luc van ((hanh va) or (hanh vi)) su tien".
• Adding a wildcard symbol may retrieve word variants: te sach vu dang ha hoi. ((hieu va) OR (hieu qua)) cao luc van ((hanh va) or (hanh vi)) su tien*.