Perhaps you should try some spelling variations:
thong cong » trong cong, tong cong, thong thong
chieu sang » chieu sach, chieu xanh, nhieu tang
hieu lang » hieu quang, nhieu tang, hieu van
hanh hang » thanh hang, hang hang, hanh han
va thong » va thuong, va phuong, he thong
cong tan » cong tac, cong san, cong thanh
toan cao » toan tap
toan ban » van ban

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: ho ((chieu sang) OR (hieu lang)) - hanh hang va thong cong tan ((toan cao) OR (toan ban))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((chieu sang) OR (hieu lang)) - hanh hang va thong cong tan ((toan cao) or (toan ban))~".
• Adding a wildcard symbol may retrieve word variants: ho ((chieu sang) OR (hieu lang)) - hanh hang va thong cong tan ((toan cao) or (toan ban))*.