Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh hai » thanh phan, thanh hoa, thanh san
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
te sach » toc sach
sach ky » sac ky, sach y, sach ty
van cau » van dau, van hau, van chat
cau luc » cau truc, cau phuc
luc ban » duc ban, cuc ban, luc bat
cua tre » cua te, cuu tre, dua tren
x hoi » o hoi, x ho, 5 hoi

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 ky nang ((x hoi) OR (xa hoi)). hieu van cau luc ban thanh hai ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang ((x hoi) OR (xa hoi)). hieu van cau luc ban thanh hai ((cua tre) OR (cua triet))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang ((x hoi) OR (xa hoi)). hieu van cau luc ban thanh hai ((cua tre) or (cua triet))*".