Perhaps you should try some spelling variations:
thanh nung » thanh tung, thanh hung, thanh dung
hieu lang » chieu sang, hieu quang, nhieu tang
dang cong » dung cong
doi hieu » doi chieu, doc hieu, doi hien
nung cao » nang cao, nhung cau, quang cao
cong van » cong vang, cong san, song van
ban hanh » ban hang
ban can » ban dan, ban hang, ban quan

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "doi hieu lang - thanh nung cao dang cong van ((ban can) OR (ban hanh))~".
• Adding a wildcard symbol may retrieve word variants: doi hieu lang - thanh nung cao dang cong van ((ban can) OR (ban hanh))*.