In the article creation process one can add tags for search. When we do so and attempt to search, the search appears to only key on the title of the article. It does not return results based on tags.
Once you tag your Knowledge base articles with keywords, the articles should appear in search results after somebody has used the keyword in their search query. Generally there is some latency after you've added tags and an article is updated - this can be anywhere from a couple of minutes to an hour.
Could you please perform a test search in your Knowledge base again, this time in a different browser or in an incognito window?
If the keyword search still doesn't pull up the right articles, could you please share a link to your Knowledge base so we can test the search ourselves?