Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
ban hanh » ban hang
hanh doi » thanh doi, hanh noi, hang doi
nam xuc » cam xuc, nam xua, nam thuc
xuc ban » duc ban, cuc ban, quoc ban
doi cua » dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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 (toc sach)) ky nang o hoi. hieu van nam xuc ban hanh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky nang o hoi. hieu van nam xuc ban hanh doi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ky nang o hoi. hieu van nam xuc ban hanh doi cua tre*.