Perhaps you should try some spelling variations:
hoc thiet » hoc thieu, hoc thuyet, hoc hien
tranh cua » doanh cua, manh cua
bang cong » dang cong, bang song, hang cong
ho thiet » hoa thiet, so thiet, hoc thieu
cua bang » chua bang, cua ban, cua dang
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: ((hoc thiet) or (ho thiet)) tach - canh tranh cua bang cong ((tan toan) or (bai toan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc thiet) OR (ho thiet)) tach - canh tranh cua bang cong ((tan toan) OR (bai toan)) cau.
• Adding a wildcard symbol may retrieve word variants: ((hoc thiet) or (ho thiet)) tach - canh tranh cua bang cong ((tan toan) or (bai toan)) cau*.