Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
cuu tre » cua tre, cau tren, cau treo
cac tuc » cac tu, cac tac, cac nuoc
sach ky » sac ky, sach y, sach ty
cac toc » cac toi, cac nuoc, cac thoi
cua te » cua tu
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.

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