Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
thanh ve » hanh ve, thanh va, thanh vien
dang xay » dang van, van xay
van cau » van dau, van hau, van chat
cuu tre » cau tren, cau treo
luc ban » duc ban, cuc ban, luc bat
cau luc » cau truc, cau phuc
tu sach » thu sach, su sach, te sach
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky nang, ky danh
vu sach » vu bach, su sach, vu khach
cua tre » cua te, cua triet, dua tren

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (vu sach)) ky dang xay hoi. hieu van cau luc ban thanh ve ((cuu tre) OR (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (vu sach)) ky dang xay hoi. hieu van cau luc ban thanh ve ((cuu tre) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (vu sach)) ky dang xay hoi. hieu van cau luc ban thanh ve ((cuu tre) OR (cua tre))".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (vu sach)) ky dang xay hoi. hieu van cau luc ban thanh ve ((cuu tre) OR (cua tre))*.