Perhaps you should try some spelling variations:
ban thinh » ban thanh, ban tinh, van thinh
thinh le » trinh ly
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, te sach, tu cach
luc ban » duc ban, cuc ban, luc bat
cau luc » cau truc, cau phuc
van cau » van dau, van hau, van chat
cua tre » cua te, cuu tre, cua triet
xay hoi » tay hoi, cay phoi, gay thoi
ky dang » ky nang, ky danh
su sach » so sach, vu sach
le cua » ly cua

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