Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
trinh toan » tinh toan, thanh toan, trinh han
duong manh » duong van
hieu lang » chieu sang, hieu quang, nhieu tang
dung manh » dung danh, hung manh, tung manh
toan tap » toan ban
toan cao » toan ban
ho hieu » ho chieu, hoi hieu, nho hieu

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 - canh trinh toan thong ((dung manh) OR (duong manh)) ((toan tap) or (toan cao))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu lang - canh trinh toan thong ((dung manh) OR (duong manh)) ((toan tap) OR (toan cao)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho hieu lang - canh trinh toan thong ((dung manh) OR (duong manh)) ((toan tap) or (toan cao))".
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - canh trinh toan thong ((dung manh) OR (duong manh)) ((toan tap) or (toan cao))*.