Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
nuoc ban » nuoc san, quoc ban, buoc ban
thanh de » hanh de, thanh ve, thanh le
thanh do » thanh pho, thanh hoa, thanh loi
te sach » toc sach
hieu te » hieu ve, hien te, hieu he
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: ((te sach) or (hoc sach)) ky nang x ho. hieu te hoc nuoc ban ((thanh de) OR (thanh do)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (hoc sach)) ky nang x ho. hieu te hoc nuoc ban ((thanh de) OR (thanh do)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (hoc sach)) ky nang x ho. hieu te hoc nuoc ban ((thanh de) OR (thanh do)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (hoc sach)) ky nang x ho. hieu te hoc nuoc ban ((thanh de) OR (thanh do)) cua tre*.