Perhaps you should try some spelling variations:
thong dung » thong cong, thong thuong
hieu lang » chieu sang, hieu quang, nhieu tang
truong va » truong dai, truong cao, truong dao
van thanh » ban thanh, van tuan
thanh cha » thanh ha, thanh nha, thanh phan
doi hieu » doi chieu, doc hieu, doi hien
trung ha » trung hoc, trung tam, trung cap
dung van » duong van, dung va, dang van

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 ((trung ha) or (truong va)) thong dung van thanh cha~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi hieu lang - thanh ((trung ha) OR (truong va)) thong dung van thanh cha.
• Adding a wildcard symbol may retrieve word variants: doi hieu lang - thanh ((trung ha) or (truong va)) thong dung van thanh cha*.