Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
sach tay » xach tay, sach hay, sach nay
hieu cao » chieu cao, hieu cac, hieu ca
hanh dai » hanh tai, hanh dao, vanh dai
van tay » van tai, van tan, van tam
cua tre » cua te, cuu tre, cua triet
va tay » va thay, ha tay, va tac
tuc va » thuc va, truc va, duc va

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 tay ((va tay) OR (van tay)) khao. hieu cao chat ((tuc va) or (tuc xa)) hanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach tay ((va tay) OR (van tay)) khao. hieu cao chat ((tuc va) OR (tuc xa)) hanh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach tay ((va tay) OR (van tay)) khao. hieu cao chat ((tuc va) or (tuc xa)) hanh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach tay ((va tay) OR (van tay)) khao. hieu cao chat ((tuc va) or (tuc xa)) hanh dai cua tre*.