Perhaps you should try some spelling variations:
hieu lang » chieu sang, hieu quang, nhieu tang
hanh tang » hanh trang, anh tang, hanh mang
tang luan » dung luan
doi hieu » doi chieu, doc hieu, doi hien
bat cong » bat dong, ban cong, ba cong
toan cau » toan cao, toan ban, toan tap
va cong » tai cong, cua cong

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi hieu lang - hanh tang luan ((bat cong) or (va cong)) tinh toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi hieu lang - hanh tang luan ((bat cong) OR (va cong)) tinh toan cau.
• Adding a wildcard symbol may retrieve word variants: doi hieu lang - hanh tang luan ((bat cong) or (va cong)) tinh toan cau*.