Perhaps you should try some spelling variations:
thanh trung » thanh tung
theo chieu » theo tieu, ho chieu, theo chu
chieu xanh » chieu sach, chieu sang, chieu tinh
trung tuan » trung thanh, trung tam, tran tuan
tuan dong » tuan duong, quan dong, luan dong
dong cong » duong cong, dung cong, dang cong
tan toan » tan tran, tap toan, van toan
bai toan » bai 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 - thanh trung tuan dong cong ((tan toan) or (bai toan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo chieu xanh - thanh trung tuan dong cong ((tan toan) OR (bai toan)) cau.
• Adding a wildcard symbol may retrieve word variants: theo chieu xanh - thanh trung tuan dong cong ((tan toan) or (bai toan)) cau*.