Perhaps you should try some spelling variations:
thanh trung » thanh tung
thieu sang » chieu sang, thieu khang, thieu quang
nhung cong » thong cong, hang cong, nhung don
hoc thieu » toc thieu, hoc hien
trung cua » truong cua, trung tuan, trung cap
dung cong » dung trong
than cau » phan cau, than cap, thanh chau
toan cau » 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 cua ((nhung cong) or (dung cong)) dan ((than cau) OR (toan cau))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thieu sang - thanh trung cua ((nhung cong) OR (dung cong)) dan ((than cau) OR (toan cau)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thieu sang - thanh trung cua ((nhung cong) or (dung cong)) dan ((than cau) OR (toan cau))".
• Adding a wildcard symbol may retrieve word variants: hoc thieu sang - thanh trung cua ((nhung cong) or (dung cong)) dan ((than cau) OR (toan cau))*.