Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
trinh quan » trinh luat, trinh han
hieu lang » chieu sang, nhieu tang, hieu van
hang cong » dang cong, hang nong, bang cong
cong manh » cong danh, duong manh, cong thanh
manh toan » thanh toan, anh tuan, tinh toan
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: ho ((hieu lang) OR (hieu quang)) - hanh ((trinh quan) or (tinh quang)) hang cong manh toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((hieu lang) OR (hieu quang)) - hanh ((trinh quan) OR (tinh quang)) hang cong manh toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((hieu lang) OR (hieu quang)) - hanh ((trinh quan) or (tinh quang)) hang cong manh toan cao".
• Adding a wildcard symbol may retrieve word variants: ho ((hieu lang) OR (hieu quang)) - hanh ((trinh quan) or (tinh quang)) hang cong manh toan cao*.