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