Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thanh ve » hanh ve, thanh va, thanh vien
su sach » so sach, vu sach
tuc van » thuc van, truc van, tuc va
luu tre » luu tru, cuu tre, luy tre
y nang » ky nang, ly nang, v nang
ve luu » ke luu, vi luu
va cau » van cau, va dau, va cao
o hoc » co hoc, mo hoc, so hoc
o hoi » co hoi, o hai, o hoa

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y nang ((o hoi) OR (o hoc)). lieu ((va cau) or (va cac)) tuc van thanh ve luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang ((o hoi) OR (o hoc)). lieu ((va cau) OR (va cac)) tuc van thanh ve luu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang ((o hoi) OR (o hoc)). lieu ((va cau) or (va cac)) tuc van thanh ve luu tre".
• Adding a wildcard symbol may retrieve word variants: su sach y nang ((o hoi) OR (o hoc)). lieu ((va cau) or (va cac)) tuc van thanh ve luu tre*.