Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh do » thanh de, thanh pho, thanh hoa
truc ban » thuc ban, truc dan, truc van
dau truc » cau truc, dai truc, doan truc
so sach » so sanh, bo sach, co sach
cuu tre » cau tren, cau treo
cua tre » cua te, cua triet, dua tren
ty nang » ky nang, ty xang, ty hang
sach ty » sach y, sach tu, sach thu
va dau » va dao
o hoi » co hoi, o hoc, o hai
x hoi » xa 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: so sach ty nang ((x hoi) OR (o hoi)). lieu va dau truc ban thanh do ((cuu tre) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty nang ((x hoi) OR (o hoi)). lieu va dau truc ban thanh do ((cuu tre) OR (cua tre))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ty nang ((x hoi) OR (o hoi)). lieu va dau truc ban thanh do ((cuu tre) or (cua tre))*".