Perhaps you should try some spelling variations:
thieu sang » chieu sang, thieu khang, thieu quang
nhung cong » dung cong, thong cong, hang cong
hoc thieu » toc thieu, hoc hien
chinh cua » chinh ca, hinh cua, chinh luan
chinh sua » chinh su, chinh luan, hinh su
hach toan » thanh toan, manh toan
tac toan » tap toan, tam toan, tich toan

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

• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thieu sang - hanh ((chinh cua) OR (chinh sua)) nhung cong ((tac toan) OR (hach toan)) cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thieu sang - hanh ((chinh cua) or (chinh sua)) nhung cong ((tac toan) OR (hach toan)) cao~".
• Adding a wildcard symbol may retrieve word variants: hoc thieu sang - hanh ((chinh cua) or (chinh sua)) nhung cong ((tac toan) OR (hach toan)) cao*.