Perhaps you should try some spelling variations:
chiet tach » chieu sach
nhung cong » dung cong, thong cong, hang cong
hieu lang » chieu sang, hieu quang, nhieu tang
hanh hang » thanh hang, hang hang, hanh han
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh 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: theo ((hieu lang) or (chiet tach)) - hanh hang va nhung cong dan toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((hieu lang) OR (chiet tach)) - hanh hang va nhung cong dan toan cau.
• Adding a wildcard symbol may retrieve word variants: theo ((hieu lang) or (chiet tach)) - hanh hang va nhung cong dan toan cau*.