Perhaps you should try some spelling variations:
dang thanh » dong thanh, dang hanh, hoang thanh
dan thanh » danh thanh, ban thanh, van thanh
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
te sach » toc sach
so sach » so sanh, bo sach, co sach
cua tre » cua te, cuu tre, cua triet
nang o » nang co, nang ho, nang ro
vi cua » vai cua, di cua
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 (so sach)) ky nang o hoi. hieu van nam thuc ((dan thanh) or (dang thanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (so sach)) ky nang o hoi. hieu van nam thuc ((dan thanh) OR (dang thanh)) vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (so sach)) ky nang o hoi. hieu van nam thuc ((dan thanh) or (dang thanh)) vi cua tre*.