1, apply for trial account and search for information.
2. Search for some projects that you have cooperated with before to see if the content of the report and related companies and contacts are consistent with the information you know;
3. Search for some items you are interested in and try to make a few phone calls to verify the accuracy of the information inside;
4. Go to the office of the information company to see the geographical location and personnel size;
5. Ask friends who work in large building materials enterprises and listen to their opinions.