Perhaps you should try some spelling variations:
sang mai » sang ma, sang tai, lang mai
hanh vai » hanh va, hanh tai, hanh van
cau tren » cu tren, dau tren, ca tren
ky sang » ky nang, ky dang, ky tang
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
dao duc » giao duc, tao duoc
cuu tre » cua tre, cau treo
ve dao » de dao, va dao, ve bao

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu cac ky sang mai hoi. hieu ve dao duc va ((hanh vai) or (hanh vi)) ((cuu tre) OR (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu cac ky sang mai hoi. hieu ve dao duc va ((hanh vai) OR (hanh vi)) ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cac ky sang mai hoi. hieu ve dao duc va ((hanh vai) or (hanh vi)) ((cuu tre) OR (cau tren))".
• Adding a wildcard symbol may retrieve word variants: tu cac ky sang mai hoi. hieu ve dao duc va ((hanh vai) or (hanh vi)) ((cuu tre) OR (cau tren))*.