In Find a Periodical, use Title Word Search to find journals available online. It's probably better to use one word only in your search. You may need to try several searches to get adequate results.
Also try the Category tab in Find a Periodical to look up journals in your discipline. Please note that the subject headings may not be specific enough (EX: Education and Careers is a subcategory under Arts and Humanities. This subcategory contains over 900 titles, which won't help you much if your field is specifically elementary education.)