Perhaps you should try some spelling variations:
dang xay » dang van, van xay
thanh de » hanh de, thanh ve, thanh do
thanh di » thanh doi, thanh do, thanh dinh
ca viet » va viet, co viet, hoa viet
ky dang » ky nang, ky danh
xay hoi » xa hoi, tay hoi, cay phoi
cao duc » dao duc, cao suc, giao duc
tu san » thu san, tu ban, tu can
san ky » sang ky, van ky, dan ky
ca duc » cua duc, ca dua, ha duc

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