Keywords are the words that describe the key concepts of your research topic. If your research question was:
Will an educational intervention increase empathy for patients with substance use disorder among emergency department staff?
Your keywords could be:
Subject headings are helpful additions to keywords as they are the specific terms under which a database has decided to index all the articles on the same topic. This system is similar to the index in the back of a book or if Twitter or Instagram came up with a list of approved hashtags and they decided what hashtags applied to posts. If you searched #COVID19 on Twitter, you would get all the tweets about COVID-19 not just the ones that people decided to use the hashtag for while others may have forgotten or used a different hashtag like #COVID.
PubMed uses MeSH terms. MeSH stands for Medical Subject Headings. The video below demonstrates how to search PubMed's MeSH database for MeSH terms to add to your search.
MeSH terms you could add to the research question above are:
Video Credit: Pace University Library
The CINAHL database uses CINAHL Subject Headings. CINAHL Subject Headings you could add to the example search include:
Watch the video below to learn how to identify appropriate CINAHL Subject Headings.
Video Credit: EBSCOhost