Perhaps you should try some spelling variations:
thieu sang » chieu sang, thieu khang, thieu quang
cong thanh » dong thanh, cong trinh, truong thanh
hoc thieu » toc thieu, hoc hien
tran tuan » tran quang, tran thanh, tranh luan
tran xuan » tran quang, tran van
cong tan » cong tac, cong san, cong ty
toan tap » toan ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc thieu sang - hanh ((tran tuan) OR (tran xuan)) nhung ((cong tan) or (cong thanh)) toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thieu sang - hanh ((tran tuan) OR (tran xuan)) nhung ((cong tan) OR (cong thanh)) toan tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thieu sang - hanh ((tran tuan) OR (tran xuan)) nhung ((cong tan) or (cong thanh)) toan tap".
• Adding a wildcard symbol may retrieve word variants: hoc thieu sang - hanh ((tran tuan) OR (tran xuan)) nhung ((cong tan) or (cong thanh)) toan tap*.