Perhaps you should try some spelling variations:
thanh trung » thanh tung
hanh trinh » canh tranh, hanh chinh
hoc thieu » toc thieu, hoc hien
dung cong » dung trong
cong bai » cuong bai, cong hai, cung bai
bai toan » bai tap
toan tap » toan ban
doi chi » doi khi
va dung » van dung, va duong, vat dung

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) or (doi chi)) xanh - ((hanh trinh) or (thanh trung)) va dung cong bai toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc thieu) OR (doi chi)) xanh - ((hanh trinh) OR (thanh trung)) va dung cong bai toan tap.
• Adding a wildcard symbol may retrieve word variants: ((hoc thieu) or (doi chi)) xanh - ((hanh trinh) or (thanh trung)) va dung cong bai toan tap*.