Perhaps you should try some spelling variations:
canh trinh » hanh trinh, canh tinh, anh trinh
thong dung » thong cong, thong thuong
hieu lang » chieu sang, hieu quang, nhieu tang
dung manh » duong manh, dung danh, hung 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) OR (canh tranh)) toan thong dung manh ((toan tap) or (toan cao))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu lang - ((canh trinh) OR (canh tranh)) toan thong dung manh ((toan tap) OR (toan cao)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho hieu lang - ((canh trinh) OR (canh tranh)) toan thong dung manh ((toan tap) or (toan cao))".
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - ((canh trinh) OR (canh tranh)) toan thong dung manh ((toan tap) or (toan cao))*.