Perhaps you should try some spelling variations:
thieu xanh » hieu manh, thien anh, thien danh
chieu xanh » chieu sach, chieu sang, chieu tinh
trung van » truong van, trung va, trung tuan
trong van » trong cac
dung cong » dung trong
cong tap » cuong tap, cong tac, cong tan
tap tren » lap tren, tac tren, tai tren
tren tau » tren thuc, tren may, tren dat

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 xanh) or (chieu xanh)) - thanh ((trung van) OR (trong van)) dung cong tap tren tau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu xanh) OR (chieu xanh)) - thanh ((trung van) OR (trong van)) dung cong tap tren tau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu xanh) or (chieu xanh)) - thanh ((trung van) OR (trong van)) dung cong tap tren tau".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu xanh) or (chieu xanh)) - thanh ((trung van) OR (trong van)) dung cong tap tren tau*.