Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sang » chieu sach, chieu xanh, nhieu tang
hieu lang » hieu quang, nhieu tang, hieu van
trung can » trung cap, trung van, trong can
dung cong » dung trong
can dung » chan dung, van dung, dan dung
cong tan » cong tac, cong san, cong thanh
tan dan » tang dan, tan doan, ban dan

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc ((chieu sang) or (hieu lang)) - thanh trung can dung cong tan dan ca~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((chieu sang) OR (hieu lang)) - thanh trung can dung cong tan dan ca.
• Adding a wildcard symbol may retrieve word variants: doc ((chieu sang) or (hieu lang)) - thanh trung can dung cong tan dan ca*.