Perhaps you should try some spelling variations:
vuc nang » cuc nang, vu nang, van nang
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
hieu va » lieu va, hieu qua
cau luc » cau truc, cau phuc
luc van » luoc van, luu van, duc van
vai cua » dai cua, lai cua, bai cua
hai cua » thai cua, dai cua, hoi cua
va cau » van cau, va cac, va dau
chuc » thuc, chu, chua

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