Perhaps you should try some spelling variations:
thieu quang » hieu quang, thien quan, trien quang
thanh trung » thanh tung
thieu sang » chieu sang, thieu khang, hieu lang
nhung cong » thong cong, hang cong, nhung don
dung cong » dung trong
trung va » truong va, trang va, trung ha
dan than » dan chan, ban than, van than
than cau » toan cau, phan cau, than cap

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) OR (thieu quang)) - thanh trung va ((nhung cong) or (dung cong)) dan than cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sang) OR (thieu quang)) - thanh trung va ((nhung cong) OR (dung cong)) dan than cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sang) OR (thieu quang)) - thanh trung va ((nhung cong) or (dung cong)) dan than cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) OR (thieu quang)) - thanh trung va ((nhung cong) or (dung cong)) dan than cau*.