Perhaps you should try some spelling variations:
hieu lang » chieu sang, hieu quang, nhieu tang
dung cong » dung trong
cong manh » cong danh, duong manh, cong thanh
manh toan » thanh toan, anh tuan, tinh toan
doc hieu » toc thieu, hoc thieu, hoc hien
tang cua » mang cua, hang cua, tang luan
toan ban » van ban
hang ca » hang va, nang cao, hang tai

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu lang - hanh ((((tang cua) or (dung luan))) or (hang ca)) dung cong manh toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu lang - hanh ((((tang cua) OR (dung luan))) OR (hang ca)) dung cong manh toan ban.
• Adding a wildcard symbol may retrieve word variants: doc hieu lang - hanh ((((tang cua) or (dung luan))) or (hang ca)) dung cong manh toan ban*.