You are probably wondering why you would need to use alternative keywords. Sometimes switching the words you use while doing a search can actually pull up more results.
Take each of your keywords and try to come up with synonyms for them. List as many as you can. Here is an example:
Use some of these alternative search terms. Mix and match when doing a search to see what brings up the most relevant information.
You can also look at the subject terms assigned to an article to find more relevant search terms.