Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
sach ky » sac ky, sach y, sach ty
qua cac » cua cac
dai hai » dai han, dai hoi, dai tai
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
dac va » duc va, dat va, dai va
x hoi » xa hoi, o hoi, x ho

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 x hoi. hieu qua cac ((dac va) OR (day va)) dai hai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang x hoi. hieu qua cac ((dac va) OR (day va)) dai hai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang x hoi. hieu qua cac ((dac va) OR (day va)) dai hai cua tre*.