Perhaps you should try some spelling variations:
cay phoi » cap phoi, tay hoi, cay cho
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
xay hoi » xa hoi, tay hoi, gay thoi
qua cau » quan cau, qua cac, qua ca
cau luc » cau truc, cau phuc
y dang » ky dang, 2 dang, _ dang
luc va » duc va, tuc va, loc va
dan va » doan va, dan ca, han va

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 y dang ((xay hoi) OR (cay phoi)). hieu qua cau luc va ((dan va) or (ban va)) cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y dang ((xay hoi) OR (cay phoi)). hieu qua cau luc va ((dan va) OR (ban va)) cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y dang ((xay hoi) OR (cay phoi)). hieu qua cau luc va ((dan va) or (ban va)) cua viet".
• Adding a wildcard symbol may retrieve word variants: tu sach y dang ((xay hoi) OR (cay phoi)). hieu qua cau luc va ((dan va) or (ban va)) cua viet*.