Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
dau tren » dau tien, dat tren, dau tieng
cau tren » cu tren, ca tren, cau treo
thanh de » hanh de, thanh ve, thanh do
luc ban » duc ban, cuc ban, luc bat
cac luc » cau luc, coc luc, cac nuoc
su sach » vu sach
hieu ve » hieu va, hieu van
dang xa » dang xay, lang xa, dang ha
ky dang » ky nang, ky danh
so sach » so sanh, bo sach, co sach
ve cac » va cac, vien cac

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) ky dang xa hoi. hieu ve cac luc ban thanh de ((cau tren) OR (dau tren))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sach)) ky dang xa hoi. hieu ve cac luc ban thanh de ((cau tren) OR (dau tren))~".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ky dang xa hoi. hieu ve cac luc ban thanh de ((cau tren) OR (dau tren))*.