Perhaps you should try some spelling variations:
nang mai » nang ma, nang tai, lang mai
su sach » so sach, vu sach
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu van
hanh va » hang va, hanh vi
hieu va » lieu va, hieu qua
bao va » bao ve, tao va, ban va
va cua » va chua, via cua, ca cua
y nang » ky nang, ly nang, v nang
cua te » cua tu
so va » so van, so vat, su va

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y nang mai hoi. ((hieu ve) or (hieu va)) bao ((so va) or (bao va)) hanh va cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang mai hoi. ((hieu ve) OR (hieu va)) bao ((so va) OR (bao va)) hanh va cua te.
• Adding a wildcard symbol may retrieve word variants: su sach y nang mai hoi. ((hieu ve) or (hieu va)) bao ((so va) or (bao va)) hanh va cua te*.