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
tong cong » trong cong, dung cong, dang cong
cong cong » cong dong, trong cong, dung cong
nhan dan » phan dau, gian dan, nhan tai
tap toan » tap doan, tap quan, bai toan
toan cao » toan ban, toan tap

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 - ((nhanh lang) or (nhan dan)) qua ((tong cong) OR (cong cong)) tap toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo chieu xanh - ((nhanh lang) OR (nhan dan)) qua ((tong cong) OR (cong cong)) tap toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo chieu xanh - ((nhanh lang) or (nhan dan)) qua ((tong cong) OR (cong cong)) tap toan cao".
• Adding a wildcard symbol may retrieve word variants: theo chieu xanh - ((nhanh lang) or (nhan dan)) qua ((tong cong) OR (cong cong)) tap toan cao*.