There are many advantages to using electronic versions including speed of the search and the ability to link to the full text of articles. Drexel University has over 100 databases for searching a wide array of topics. To determine which are best for your topic, check the Resources Guides or review the database descriptions available through the library's web site. In short, indexes, whether online or in print, will provide you with citations to periodical articles on various subjects. Selecting additional resources is something that I can do.
Lets take an example in order to think about other resources.
Let's say you are writing a paper about Zionism . You have introduced yourself to the subject by reading an encyclopedia article. You have checked the library's catalog for books and you have searched the databases to track down journal articles. Try to find an Almanac, Historical Atlas, National or World Yearbook, or perhaps a Chronology. Look for biographies, obituaries, and Who's Who publications.