Perhaps you should try some spelling variations:
doanh doanh » toan doanh, doanh hoan, doanh thanh
thieu sang » chieu sang, thieu khang, thieu quang
tan thanh » tran thanh, tang thanh, toan thanh
thanh cay » thanh tay, nhanh cay, thanh ca
luan han » luan hoan, luan phan, luan san
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: toc thieu sang - doanh doanh ((luan han) or (luan van)) cong tan thanh cay~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc thieu sang - doanh doanh ((luan han) OR (luan van)) cong tan thanh cay*.