There are several ways to find Subject Headings when you search.
One way to find subject headings:
Another way to find subject headings:
Credits: adapted from MIT Libraries
Subject Heading - describes the content of items within a database using what is called "controlled vocabulary"
Controlled Vocabulary - pre-determined terms and words used to classify items within a database so that they can be sorted into subjects.
You can use subject headings to find items on a topic. This can be especially helpful because of alternate terms or spellings for a word, such as Edema, which has formerly--and in some communities is still called--Dropsy, Anasarca, and Hydrops.
| Keyword Search | Subject Search |
|---|---|
| Natural language words describing your topic - good to start with | Pre-defined "controlled vocabulary" words used to describe the content of each item (book, journal article) in a database |
| More flexible to search by - can combine together in many ways | Less flexible to search by - need to know the exact controlled vocabulary term |
| Database looks for keywords anywhere in the record - not necessarily connected together | Database looks for subjects only in the subject heading or descriptor field, where the most relevant words appear |
| May yield too many or too few results | If too many results - also uses subheadings to focus on one aspect of the broader subject |
| May yield many irrelevant results | Results usually very relevant to the topic |
Chart via MIT Libraries
Subject Headings are super helpful when doing historical research because of the historical changes in names of diseases and conditions over time.
They can also help us pinpoint date ranges, geographical locations, and even social groupings.
For example, if I'm researching historical treatments or writings on Diabetes, I will do a very basic subject search in the National Library of Medicine Digital Collections, but I run a keyword search, then use the Subjects on the left hand side of my results to help me narrow.
I see a of results for quite a few different subjects including General Surgery, Eye Diseases, but "Diabetes Mellitus" does eventually appear as a subject heading, so i select that and I find several posters, a video, and some pre 1900 publications on the topic.
This is one way that subject searching can be useful when doing some historical research. You also have options to narrow and filter by date ranges and geographic areas too the same way you do for subjects.