Sometimes you may decide that you do not want PubMed to interpret your search terms. For example, you may find that it is interpreting them incorrectly, or in a way that you did not want or expect. Or, you may be running a more structured search for a project like a systematic or scoping review, where you would likely want to have more control over the search and ensure it is reproducible.
If you do not want PubMed to interpret your search terms, you can turn the ATM feature off by using one of the following methods:
Tag the term with a specific field code (example: hemorrhage[tw], which searches text word)
Put the term into quotation marks (example: "hemorrhage")
Use truncation
What is ATM (Automatic Term Mapping)?
Automatic Term Mapping (ATM) is a process that happens in the background of most PubMed searches. The database takes the terms that you have entered into the search box and attempts to interpret them and map them to the appropriate MeSH Terms.
In most everyday or casual searches, the ATM feature will help your search by not requiring you to put as many terms into the search box or build more complex search queries. However, sometimes the ATM process can go in an unexpected or undesired direction.
For example, (hemorrhage) returns to many results because it maps to blood.
Another example is sputum culture.
How do I see how ATM is mapping terms?
To see how your terms are being mapped, you can view your Search Details in your Search History.
Click on the Advanced Search link underneath the search box
Scroll to the bottom of the Advanced Search page to view your Search History
Find the line of your Search History that you would like to look at
Click on the arrow icon underneath the heading Search Details to expand out the details section
This will then display the search you entered, the full search that was actually run by the database, and all of the individual term translations that took place