Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hanh dai » hanh tai, hanh dao, vanh dai
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
cac luc » cau luc, coc luc, cac nuoc
luc van » luoc van, luu van, duc van
y tang » ky tang, 6 tang, 5 tang
7 tang » 6 tang
ma hoi » mai hoi, xa hoi, ma hoa
cua su » qua su

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ((y tang) or (7 tang)) ma hoi. hieu va cac luc van hanh dai cua su~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y tang) OR (7 tang)) ma hoi. hieu va cac luc van hanh dai cua su.
• Adding a wildcard symbol may retrieve word variants: tu sach ((y tang) or (7 tang)) ma hoi. hieu va cac luc van hanh dai cua su*.