We sell Carbon Brushes, a part of electric tools, in europe and mostly in germany. In german carbon brushes got several synonyms and in order to test the search volume i started a campaign whereby I used the several synonyms as different keywords. You see those in the attachment. But somehow, if I use those keywords to search for our products no advertisings show up. You also see in the results that there are no impressions of our advertisements for the specific keywords.
How come that they are not showing up? Should I make a different ad group for each keyword maybe? or are there other explanations? like there is not enough search volume or listings for the specific keywords. I hope you guys can help me out!