Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
thong manh » thong minh, thong mang, thong danh
hieu lang » chieu sang, nhieu tang, hieu van
manh toan » thanh toan, anh tuan, tinh toan
trung va » truong va, trung ha, trung tam
trang va » tran van, hang va
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: ho ((hieu lang) OR (hieu quang)) - hanh ((trung va) or (trang va)) thong thong manh toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((hieu lang) OR (hieu quang)) - hanh ((trung va) OR (trang va)) thong thong manh toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((hieu lang) OR (hieu quang)) - hanh ((trung va) or (trang va)) thong thong manh toan cau".
• Adding a wildcard symbol may retrieve word variants: ho ((hieu lang) OR (hieu quang)) - hanh ((trung va) or (trang va)) thong thong manh toan cau*.