Perhaps you should try some spelling variations:
te sach » toc sach
sach vu » sach va, sach tu, sach uu
vu nang » vuc nang, va nang, vu dang
hieu va » lieu va, hieu qua
luc van » luoc van, luu van, luc va
duc van » duc va, duc tan, duc manh
hanh ve » hanh vi, hanh va, hanh kem
nang o » nang co, nang ho, nang ro
va dao » ca dao
o hoi » co hoi, o hoc, o hai
ve su » va su
kien » bien, vien, tien

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 nang o hoi. hieu va dao ((luc van) or (duc van)) hanh ve su kien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach vu nang o hoi. hieu va dao ((luc van) OR (duc van)) hanh ve su kien.
• Adding a wildcard symbol may retrieve word variants: te sach vu nang o hoi. hieu va dao ((luc van) or (duc van)) hanh ve su kien*.