Perhaps you should try some spelling variations:
hieu lang » chieu sang, hieu quang, nhieu tang
cong vang » cong lang, cong quang, cong ngang
thanh cao » thanh ca, thanh cac, thanh thao
doi hieu » doi chieu, doc hieu, doi hien
trung va » truong va, trang va, trung ha
cong san » cong tac
tung va » tuong va, dung va, vung va

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi hieu lang - thanh ((tung va) or (trung va)) thong ((cong vang) or (cong san)) thanh cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi hieu lang - thanh ((tung va) OR (trung va)) thong ((cong vang) OR (cong san)) thanh cao.
• Adding a wildcard symbol may retrieve word variants: doi hieu lang - thanh ((tung va) or (trung va)) thong ((cong vang) or (cong san)) thanh cao*.