Scientific Journal Indexes
There are many scientific journal indexes; they share a lot of characteristics but differ from one another and are each suitable for a different set of uses. A continuously-updated list is available on Wikipedia, Here are a few points to consider when deciding which index to use for your literature searches. First, you need to know which indexes are available to you personally or through your institution’s library. Pubmed, an online-version of the Index Medicus, is a service of the American National Library of Medicine and is freely available online to any user. Other indexing services, such as Scopus, and Embase, both published by the publishing giant Elsevier are available only with a subscription. PsychInfo, published by the American Psychological Association is available through a number of vendors with a subscription and also offers individual paid-use options. Next, you need to know which types of literature and/or information sources you would like to access. Pubmed contains 27 million citations, covering all of the Medline database with some additional citations. It is a biomedical and life sciences database that includes only journal articles. Pubmed is part of the Entrez series of databases of (among others) online books (quite limited), genes and proteins. Embase is also focused mainly on the biomedical sciences but it offers a much more in-depth coverage of drugs and pharmacology and hence is a better resource for studies on topics of pharmaceuticals including pharmacovigilance and drug development. It currently includes 32 million citations encompassing all of Medline and many additional journals, mainly from Europe. Unlike Pubmed, it provides citations from conference abstracts in addition to journal articles. Scopus is an inter-disciplinary index that covers, in addition to biomedical journal articles, titles from physical sciences, social sciences and humanities. The Scopus index includes over 54 million citations of journal articles, books, book chapters, and conference abstracts covering all of Medline and Embase in addition to other sources. Thus, it may be useful for studies of an interdisciplinary nature, such as health policy or health economics topics. PsychInfo is a database of publications in behavioral science, social science and mental health. It covers approximately 3.5 million records including journal articles, book chapters, books, and dissertations. Studies on a wide range of medical topics including psychiatric studies, pediatric development studies and others, may benefit from literature searches on PsychInfo.What type of search would you like to perform? Pubmed and Embase index journal articles by subject headings and subheadings that are terms from the biomedical sciences. Pubmed automatically maps any searched term to a heading, and you can run an advanced search to map to a subheading from a tree of available possibilities. EmBase does not automatically map your search words, rather, you can choose the subheadings manually from a list. Scopus, because it searches a few databases simultaneously, only offers natural-language search options with no option for headings. All indexes offer extensive search-limiting options by article characteristics (e.g. year of publication, languages, type of publication and others). Bibliometric studies, as well as systematic reviews and meta-analyses, should be performed using more than a single database, to ensure that relevant records are not missed. Naturally, any such study would have to include a step of consolidation of duplicate records. All of the above-mentioned resources index only peer-reviewed publications and they each employ their own selection process for quality prior to including a journal in the index. Thus, they are all good resources to assist in weeding-out sub-par publications from your research.
The next post will focus on Sci-Hub, the pirate repository of academic publications