Perhaps you should try some spelling variations:
thong cong » trong cong, tong cong, thong thong
hieu lang » chieu sang, hieu quang, nhieu tang
van thang » van thanh, van khang, van hang
van quang » van quan, tran quang, van tuan
tan thong » toan thong, tran thong, tao thong
doc hieu » toc thieu, hoc thieu, hoc hien
cong tan » cong tac, cong san, cong thanh

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu lang - thanh cong ((van thang) or (van quang)) cong tan thong cong~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu lang - thanh cong ((van thang) OR (van quang)) cong tan thong cong*.