Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh di » hanh vi, hanh de, hang di
luc van » luoc van, luu van, duc van
cac luc » cau luc, coc luc, cac nuoc
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
sach va » sach xa, sach ha, sach dao
sach v » sach y, sach 2, sach vay
di cua » dai cua, doi cua, de cua
cua tu » cua tuc, cua su, cua cu

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 v) or (sach va)) ((nang ma) or (mang may)) hoi. hieu va cac luc van hanh di cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach v) OR (sach va)) ((nang ma) OR (mang may)) hoi. hieu va cac luc van hanh di cua tu.
• Adding a wildcard symbol may retrieve word variants: te ((sach v) or (sach va)) ((nang ma) or (mang may)) hoi. hieu va cac luc van hanh di cua tu*.