Perhaps you should try some spelling variations:
hieu sang » chieu sang, hieu lang, hieu quang
doanh cao » doanh co, doanh bao, doanh dao
doanh cho » danh cho, doanh co, doanh chu
doc hieu » toc thieu, hoc thieu, hoc hien
ban gian » dan gian, ban giao, van giang
van gian » van giang, dan gian, van giao
cong tac » cong ty

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 sang - hanh ((ban gian) OR (van gian)) trong cong tac ((doanh cao) or (doanh cho))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu sang - hanh ((ban gian) OR (van gian)) trong cong tac ((doanh cao) OR (doanh cho)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu sang - hanh ((ban gian) OR (van gian)) trong cong tac ((doanh cao) or (doanh cho))".
• Adding a wildcard symbol may retrieve word variants: doc hieu sang - hanh ((ban gian) OR (van gian)) trong cong tac ((doanh cao) or (doanh cho))*.