Perhaps you should try some spelling variations:
thong cong » trong cong, tong cong, thong thong
hieu lang » chieu sang, hieu quang, nhieu tang
hieu quan » hieu qua, lieu quan, thien quan
hanh tran » hanh trang, thanh tran, hanh tram
van thong » van thuong, van phong, va thong
van thanh » ban thanh, van tuan
thanh ban » thanh san, thanh van, thanh bac
tran van » luan van
cong van » cong vang, cong san, song van

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: hoc ((hieu lang) OR (hieu quan)) - hanh tran van thong cong van thanh ban~.
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu lang) or (hieu quan)) - hanh tran van thong cong van thanh ban*.