Perhaps you should try some spelling variations:
lang van » dang van, tang van, hoang van
hieu cua » hieu qua, dieu cua, bieu cua
cac quoc » cac nuoc, cac cuoc, cao quoc
quoc ban » quoc bao, quoc lan, quoc quan
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
lang xa » lang ha, dang xay
ban anh » ban hanh, ban banh, ban danh
anh hai » lanh hai, manh hai, anh thai
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet

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 ty ((lang xa) or (lang van)) hoi. hieu cua cac quoc ban anh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((lang xa) OR (lang van)) hoi. hieu cua cac quoc ban anh hai cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ty ((lang xa) or (lang van)) hoi. hieu cua cac quoc ban anh hai cua tre*.