Perhaps you should try some spelling variations:
thanh doi » thanh loi, thanh moi, thanh do
cau tren » cu tren, dau tren, ca tren
thanh di » thanh de, thanh do, thanh dinh
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
cac duc » cac du, cac dac, cac nuoc
cao duc » dao duc, cao suc, giao duc
tu san » thu san, tu ban, tu can
san ky » sang ky, van ky, dan ky
ma hoi » mai hoi, xa hoi, ma hoa

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 nang ma hoi. hieu va ((cac duc) OR (cao duc)) va ((thanh di) or (thanh doi)) cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu san ky nang ma hoi. hieu va ((cac duc) OR (cao duc)) va ((thanh di) OR (thanh doi)) cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu san ky nang ma hoi. hieu va ((cac duc) OR (cao duc)) va ((thanh di) or (thanh doi)) cau tren".
• Adding a wildcard symbol may retrieve word variants: tu san ky nang ma hoi. hieu va ((cac duc) OR (cao duc)) va ((thanh di) or (thanh doi)) cau tren*.