One of the major advantages of database searching is its ability to search for the language authors and researchers actually use. “Keyword” or “natural language” searching, as it’s sometimes called, removes any level of mediation between the user looking for content and the author creating it, which can be useful, especially when one is looking for very specific information on a subject that is not especially well documented.
However, keyword searching can be a little disorderly. Terms can have multiple meanings or be used in different ways in various disciplines. Additionally, different authors may refer to the same topic in different ways, depending on their views or intended audience, such as using common terms instead of technical ones. Finally, keyword searching is not very good at distinguishing between articles that are focused on a subject and those that only use the search term in passing. Like plugging a term into Google, ProQuest will just find everywhere a term appears in the database and present those results, and the more often the term appears in an article, the higher it will be on the list. The number of results can quickly climb out of control when only keywords are used—especially if the full text of articles is being searched.
In order to mitigate the unstructured nature of keyword searching, ProQuest also groups materials by subject, and within Nursing and Allied Health, uses two different sets of headings. The first of these is their own creation, while the second is the Medical Subject Headings, or MeSH, created by the U.S. National Library of Medicine. I prefer using the later, because it is more robust.
For example, if I look up cirrhosis in the ProQuest thesaurus, I get ‘liver cirrhosis’, with ‘disease’ and ‘liver disease’ as broader terms. However, in the MeHS thesaurus, which is available at http://www.nlm.nih.gov/mesh/MBrowser.html, I get the following list of headings:
Liver Cirrhosis, Alcoholic
Hepatic Cirrhosis, Alcoholic
Liver Cirrhosis, Biliary
Biliary Cirrhosis, Primary
Biliary Cirrhosis, Primary, 1
Biliary Cirrhosis, Secondary
Liver Cirrhosis, Obstructive
Primary Biliary Cirrhosis
Secondary Biliary Cirrhosis
Liver Cirrhosis, Experimental
Cirrhosis, Experimental Liver
Experimental Liver Cirrhosis
Hepatic Cirrhosis, Experimental
Berry Aneurysm, Cirrhosis, Pulmonary Emphysema, and Cerebral Calcification
Cerebral Aneurysm-Cirrhosis Syndrome
Biliary Cirrhosis, Primary, 2
Biliary Cirrhosis, Primary, 3
Endemic Tyrolean Infantile Cirrhosis
CIRH1A protein, human
cirrhosis, autosomal recessive 1A (cirhin), human
Cirrhosis, familial, with deposition of abnormal glycogen
Cirrhosis, Familial, with Pulmonary Hypertension
Indian Childhood Cirrhosis
Familial primary biliary cirrhosis
Hypermanganesemia with Dystonia Polycythemia and Cirrhosis
Hypermanganesemia With Dystonia, Polycythemia, And Cirrhosis
North American Indian Childhood Cirrhosis
primary biliary cirrhosis antigen 95k
As highlighted by the above list of terms, MeSH is a much more extensive organizational system than that provided by ProQuest. In theory, all of the articles dealing with cirrhosis in a substantive way should fall somewhere within this system of terms.
Subject searching can be used in two different ways. The first of these is to just search for a subject and browse through the results. For a topic that is less common, this can be useful, but often times this will generate too many results to be efficient. Unless it is important to be comprehensive in one’s research and to access all the materials on a given subject, this probably isn’t the best approach to take.
The second method is to use subject headings to give a little control to a keyword search and is how I would suggest using them. Returning to the example of cirrhosis above, assume I’m looking for information on treating primary biliary cirrhosis. If I searched for both terms as keywords(treatment and primary biliary cirrhosis), I would recall over 3000 articles, which is more than is reasonable to go through. However, if I use the subject heading “Biliary Cirrhosis, Primary” by entering the term in the search box and selecting subject headings in the drop down menu on the right, and then search for treatment as a keyword (so, my actual search phrase is “treatment* AND su(Biliary Cirrhosis, Primary)’), I’ve limited my results to twenty, a much more manageable number.
Keep subject searching in mind while working on your projects. If your searches are always returning a large amount of results that don’t seem to quite be relevant, it can be a useful tool in creating a more effective and efficient search.
And of course, come see me in the Library if you have any questions or need help.