Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
sach vu » sach va, sach tu, sach uu
hanh ve » hanh vi, hanh va, hanh kem
luc van » luoc van, luu van, duc van
cao luc » bao luc, cao duc, cao suc
su tien » su kien, su hien, tu tieng
hieu va » lieu va
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
ve su » va su

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