Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hanh tai » thanh tai, hang tai, han tai
hieu van » hieu va, thien van, lieu va
cuc ban » cua ban, cuu ban, duc ban
tai cua » thai cua, tai cuc, tri cua
cac ban » cac dan, cac van, can ban
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va
nang xa » nang x, lang xa, nang ma
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: thu sach ky nang xa hoi. ((hieu ve) or (hieu van)) cam ((cuc ban) OR (cac ban)) hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang xa hoi. ((hieu ve) OR (hieu van)) cam ((cuc ban) OR (cac ban)) hanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang xa hoi. ((hieu ve) or (hieu van)) cam ((cuc ban) OR (cac ban)) hanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang xa hoi. ((hieu ve) or (hieu van)) cam ((cuc ban) OR (cac ban)) hanh tai cua tre*.