Perhaps you should try some spelling variations:
chiet tach » chieu sach
nhieu tang » chieu sang, hieu lang, nhiet nang
hanh trang » thanh trung, canh tranh, hanh trinh
nhung cong » dung cong, thong cong, hang cong
trang va » tran van, hang va
cong tap » cuong tap, cong tac, cong tan
tap toan » tap doan, tap quan, bai toan
toan cau » 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: hoc ((chiet tach) or (nhieu tang)) - hanh trang va nhung cong tap toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chiet tach) OR (nhieu tang)) - hanh trang va nhung cong tap toan cau.
• Adding a wildcard symbol may retrieve word variants: hoc ((chiet tach) or (nhieu tang)) - hanh trang va nhung cong tap toan cau*.