Perhaps you should try some spelling variations:
thanh do » thanh de, thanh pho, thanh hoa
cay phoi » cap phoi, tay hoi, cay cho
thanh di » thanh doi, thanh de, thanh dinh
ca viet » va viet, co viet, hoa viet
duc van » duc va, duc tan, duc manh
ky dang » ky nang, ky danh
xay hoi » xa hoi, tay hoi, gay thoi
tu san » thu san, tu ban, tu can
ca duc » cao duc, cua duc, ca dua
san ky » sang ky, van ky, dan ky
qua ca » qua cac, qua cua, qua cai

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu san ky dang ((xay hoi) OR (cay phoi)). hieu qua ca duc van ((thanh di) or (thanh do)) ca viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu san ky dang ((xay hoi) OR (cay phoi)). hieu qua ca duc van ((thanh di) OR (thanh do)) ca viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu san ky dang ((xay hoi) OR (cay phoi)). hieu qua ca duc van ((thanh di) or (thanh do)) ca viet".
• Adding a wildcard symbol may retrieve word variants: tu san ky dang ((xay hoi) OR (cay phoi)). hieu qua ca duc van ((thanh di) or (thanh do)) ca viet*.