Journals are usually published in a specified period, published by volume, issue, year, month, etc. The contents are usually systematic and professional, including many types of articles, such as research papers, reviews, news, reports, etc. Periodicals usually have a fixed publishing cycle, such as monthly, bimonthly or quarterly.
A publication is a kind of publication, including magazines, newspapers, books, etc. They can be published regularly or irregularly. The contents of publications are usually extensive and can involve many fields, including news, reviews, novels, poems, essays, cartoons and so on. Publications usually have no fixed publishing cycle, and can be published at different time intervals such as monthly, quarterly and annual.