Perhaps you should try some spelling variations:
cong thuong » hang thuong
chieu sang » chieu sach, chieu xanh, nhieu tang
thuong dan » huong dan, thuong han, thuong dam
hieu lang » hieu quang, nhieu tang, hieu van
dung cua » dung cho
dan toan » van toan, dan than, manh toan
toan cao » toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: ho ((chieu sang) or (hieu lang)) - thanh ((dung cua) OR (dung luan)) cong thuong dan toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((chieu sang) OR (hieu lang)) - thanh ((dung cua) OR (dung luan)) cong thuong dan toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((chieu sang) or (hieu lang)) - thanh ((dung cua) OR (dung luan)) cong thuong dan toan cao".
• Adding a wildcard symbol may retrieve word variants: ho ((chieu sang) or (hieu lang)) - thanh ((dung cua) OR (dung luan)) cong thuong dan toan cao*.