There is often a large difference between popular magazines and scholarly journals. Magazines don't require deep background knowledge of a topic. They may cover serious issues, but entertaining the reader is stressed. Journals are written by and for scholars and emphasize original research. Facts and analysis are stressed over entertainment.
Some indexes are on computers and some are in paper format.
Each index has its own procedures and the information will look different, but all include the same basic information needed to locate an article. Some indexes cover mainly popular magazines and some only index scholarly journals. Ask the librarian what indexes are available at your campus and which would be most useful for your research. We occasionally add new indexes, and other campuses may have ones useful for you. If your search of indexes isn't successful, talk to the library staff.