Perhaps you should try some spelling variations:
thanh trung » thanh tung
thieu sang » chieu sang, thieu khang, thieu quang
cong ngang » cong nhan, cong quang, cong lang
hoc thieu » toc thieu, hoc hien
hua khong » hoa khong, cua khong, hoac khong
hoa cong » cua cong, va cong, hoa co
than cau » toan cau, phan cau, than cap
toan cao » toan ban, toan tap

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 - thanh trung ((hua khong) or (hoa cong)) cong ngang ((than cau) or (toan cao))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thieu sang - thanh trung ((hua khong) OR (hoa cong)) cong ngang ((than cau) OR (toan cao)).
• Adding a wildcard symbol may retrieve word variants: hoc thieu sang - thanh trung ((hua khong) or (hoa cong)) cong ngang ((than cau) or (toan cao))*.