On occasion, I get asked why no articles from certain journals show up when a patron does a search in one of the databases.  Usually the reason is because the patron is searching an electronic journal collection rather than an index.

Indexes list articles from journals (and sometimes books and conferences) with their bibliographic information and add extras such as subject information and abstracts.  Usually the abstracts are those provided by the authors, but some indexes actually have professionals read every article and write a summary. When you run a keyword search in an index, you generally are searching the bibliographic information and the added subject and abstract information, but not the full-text of the articles.  Once you find an article you’re interested usually you can click to find the article either directly or through the BUInfoLink button.  PubMed is one major exception to this rule.

The journals in indexes can vary widely from a handful in a very specific discipline to thousands over a wide variety of subjects.  Different indexes have different criteria for which articles and journals they include: some include reviews and letters to the editors and others only research articles; some include popular periodicals and others only include peer-reviewed journals.  Generally, if you hunt around you can find a list of journals that are covered in that index along with the dates of coverage.  Alternatively, if you check Ulrich’s, you can find which indexes include the journal you’re interested in.

Electronic journal collections are exactly what they sound like.  They are collections of specific journals, and often you can browse or search through those journals.  When you search you often have the option of searching the full-text of an article in addition to the standard bibliographic data and abstracts.  Some journal collections add subject information, but some do not.

Usually electronic journal collections are managed by a single publisher and list all the articles from the journals they publish.  Some publishers might be very subject specific, but others like ScienceDirect are from very large publishers and cover many areas.  JStor and Project Muse are both examples of electronic journal collections that are not publisher specific but they tend to only contain older articles and their focus is in the humanities rather than the sciences.

Looking back at the list of databases by subject, most of these databases are indexes.  However, the ones with “Online” or “Digital Library” in their names are more electronic journal collections than indexes, but they’re still relatively comprehensive.