Perhaps you should try some spelling variations:
thieu khang » chieu khong, thieu quang
thieu sang » chieu sang, thieu quang, hieu lang
canh thanh » canh tranh, danh thanh, anh thanh
nhung cong » dung cong, thong cong, nhung don
thanh van » thanh san, thanh toan, thanh phan
hang cong » dang cong, hang nong, bang cong
van tuan » van quan, van ban, anh tuan
tuan cau » toan cau, quan cau, tuan cu

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) OR (thieu khang)) - canh thanh van ((nhung cong) OR (hang cong)) van tuan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sang) OR (thieu khang)) - canh thanh van ((nhung cong) or (hang cong)) van tuan cau~".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) OR (thieu khang)) - canh thanh van ((nhung cong) or (hang cong)) van tuan cau*.