There is no special criteria for google to show articles based on any keyword. The only criteria is that your article should be good with enough contents related to the subject of your articles. As you gain experience in writing articles. You will come to know, how to write good articles. For the time being just concentrate on writing grammatically correct articles with good content, because such articles will help you in getting Google adsense. So, don't worry too much about google not showing your articles. When I started writing articles, I too used to search my articles in google. But now since I am writing so many articles, I don't have time to do so. Even then I am earning 100s of dollars per month in Google adsense. One more point, It takes some tome for any article to get indexed in google. Till then keep up the good work.