Perhaps you should try some spelling variations:
quoc lan » quoc ban, nuoc luan, quoc quan
cam quoc » cac quoc, cao quoc, nam quoc
hieu va » lieu va, hieu qua
lan anh » van anh, tuan anh
su sach » so sach, vu sach
ly nang » ky nang, ly hang, ly vang
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, v nang, may nang
va cam » va cham, va cac, va cao
anh ve » hanh ve, anh va, anh viet
ve cua » le cua, de cua, te cua
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((y nang) OR (ly nang)) ((x hoi) OR (o hoi)). hieu va cam quoc lan anh ve cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((y nang) OR (ly nang)) ((x hoi) or (o hoi)). hieu va cam quoc lan anh ve cua tre~".
• Adding a wildcard symbol may retrieve word variants: su sach ((y nang) OR (ly nang)) ((x hoi) or (o hoi)). hieu va cam quoc lan anh ve cua tre*.