Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
cac dac » cac dai, cac bac, cac tac
dau hai » dai hai, dau ha, cau hai
hai cuu » hai cua, hai chu, hai cuc
cuu tre » cua tre, cau tren, cau treo
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 ty nang x ho. hieu qua ((cac dac) or (cac dan)) va dau hai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty nang x ho. hieu qua ((cac dac) OR (cac dan)) va dau hai cuu tre.
• Adding a wildcard symbol may retrieve word variants: thu sach ty nang x ho. hieu qua ((cac dac) or (cac dan)) va dau hai cuu tre*.