Perhaps you should try some spelling variations:
thieu sang » chieu sang, thieu khang, thieu quang
hoc thieu » toc thieu, hoc hien
trinh qua » trinh quan, trinh quang, trinh luat
trinh cua » tinh cua, trinh luat, trinh quan
cong dan » cong tan, huong dan, cong dong
cong san » cong tac
than cau » toan cau, phan cau, than cap

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 ((trinh qua) OR (trinh cua)) nhung ((cong dan) OR (cong san)) than cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thieu sang - hanh ((trinh qua) OR (trinh cua)) nhung ((cong dan) or (cong san)) than cau~".
• Adding a wildcard symbol may retrieve word variants: hoc thieu sang - hanh ((trinh qua) OR (trinh cua)) nhung ((cong dan) or (cong san)) than cau*.