Perhaps you should try some spelling variations:
thong cong » trong cong, thong thong, phong chong
hieu lang » chieu sang, hieu quang, nhieu tang
lanh manh » lanh tranh, lan anh, anh anh
tong cong » trong cong, cong cong, dung cong
doi hieu » doi chieu, doc hieu, doi hien
van manh » van minh, van anh, van hanh
san toan » van toan, dan toan, manh 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: doi hieu lang - ((lanh manh) or (van manh)) cua ((thong cong) or (tong cong)) san toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi hieu lang - ((lanh manh) OR (van manh)) cua ((thong cong) OR (tong cong)) san toan cao.
• Adding a wildcard symbol may retrieve word variants: doi hieu lang - ((lanh manh) or (van manh)) cua ((thong cong) or (tong cong)) san toan cao*.