Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thu sach » tu sach, thuat sach, thu hoach
qua cac » cua cac
cac dac » cac dan, cac dai, cac bac
dau hai » dai hai, dau ha, cau hai
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
dac va » duc va, day va, dat va
va dau » va dao

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