Perhaps you should try some spelling variations:
theo chieu » theo tieu, ho chieu, theo chu
chieu xanh » chieu sach, chieu sang, chieu tinh
nhanh lang » nhanh quang, nhanh thang, nhan dang
hanh tung » thanh tung, manh tung, hanh dung
dung cong » dung trong
cua dung » cua dang, cua dong, qua dung
tap toan » tap quan, bai toan
tap doan » tap quan

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: theo chieu xanh - ((hanh tung) or (nhanh lang)) cua dung cong ((tap toan) OR (tap doan)) ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo chieu xanh - ((hanh tung) OR (nhanh lang)) cua dung cong ((tap toan) OR (tap doan)) ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo chieu xanh - ((hanh tung) or (nhanh lang)) cua dung cong ((tap toan) OR (tap doan)) ban".
• Adding a wildcard symbol may retrieve word variants: theo chieu xanh - ((hanh tung) or (nhanh lang)) cua dung cong ((tap toan) OR (tap doan)) ban*.