Perhaps you should try some spelling variations:
phuong dong » phuong dung, phuong hoang, chuong duong
chieu xanh » chieu sach, chieu tinh, hieu manh
chieu sang » chieu sach, hieu lang, nhieu tang
tang van » dang van, hoang van, trong van
dong tac » cong tac, dong tai, dong bac
tac toan » tap toan, tam toan, hach toan
toan cau » toan cao, toan ban, toan tap
tang va » trang va, thang va, tang vat

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: theo ((chieu xanh) OR (chieu sang)) - anh ((tang va) OR (tang van)) phuong dong tac toan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo ((chieu xanh) or (chieu sang)) - anh ((tang va) OR (tang van)) phuong dong tac toan cau~".
• Adding a wildcard symbol may retrieve word variants: theo ((chieu xanh) or (chieu sang)) - anh ((tang va) OR (tang van)) phuong dong tac toan cau*.