Perhaps you should try some spelling variations:
tang mai » tang ma, tang tai, lang mai
than soc » than hoc, than so, thanh son
ban hang » ngan hang
ky tang » ky nang, ky dang, kho tang
mai hoi » mai khoi, dai hoi, lai hoi
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu cac ky tang mai hoi. hieu qua ((than soc) OR (than doc)) ban hang va ((cua tre) OR (cuu tre))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cac ky tang mai hoi. hieu qua ((than soc) or (than doc)) ban hang va ((cua tre) OR (cuu tre))~".
• Adding a wildcard symbol may retrieve word variants: tu cac ky tang mai hoi. hieu qua ((than soc) or (than doc)) ban hang va ((cua tre) OR (cuu tre))*.