Perhaps you should try some spelling variations:
thinh doan » chinh doanh, hinh toan, thi doan
cong thang » cong thanh, cang thang, cong thong
hieu lang » chieu sang, hieu quang, nhieu tang
dang cong » dung cong
toc hieu » toc thieu, doc hieu, hoc thieu
doan van » doan va, hoang van, luan van
van dang » van dong, van dung, van nang
phan dau » phan tu, hang dau
phan van » pham van, thanh van, luan van

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc hieu lang - thinh doan van dang cong thang ((phan dau) or (phan van))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc hieu lang - thinh doan van dang cong thang ((phan dau) OR (phan van))*.