Perhaps you should try some spelling variations:
thieu xanh » chieu xanh, hieu manh, thien anh
hoc thieu » toc thieu, hoc hien
tong cong » trong cong, cong cong, dung cong
tac toan » tap toan, hach toan, tich toan
tam toan » tap toan, tam than, pham toan
cong cu » chung cu
cu tong » cuu tong, cua tong, tu tong

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc thieu xanh - thanh cong cu tong cong ((tac toan) or (tam toan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thieu xanh - thanh cong cu tong cong ((tac toan) OR (tam toan)) cau*.