Perhaps you should try some spelling variations:
thanh trung » thanh tung
thieu xanh » hieu manh, thien anh, thien danh
chieu xanh » chieu sach, chieu sang, chieu tinh
trung van » truong van, trong van, trung va
dung cong » dung trong
van dung » van dong, xay dung, tin dung
tac tren » rac tren, tai tren, tac truyen
tap tren » lap tren, tai tren, tap truyen

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 xanh) OR (chieu xanh)) - thanh trung van dung cong ((tac tren) OR (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 dung cong ((tac tren) OR (tap tren)) tau~".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu xanh) or (chieu xanh)) - thanh trung van dung cong ((tac tren) OR (tap tren)) tau*.