1. Click in the query box. Type heart attack and click Enter or Go. The first 20 references matching your search will appear. Near the top look for "Items 1 to 20 of X." X indicates the total number of search results.

2. To view automatic term mapping in action, go to the Advanced Search screen. You'll see your search listed under Most Recent Queries. Click on the Search number, and select Details from the menu that pops up. Example

The Search Details page shows how PubMed has automatically mapped your search to include myocardial infarction, a synonym for heart attack. And, it is automatically searching the term as a MeSH term (to include all variations and synonyms).

Note that it is possible to edit your search in the Query Translation box. Click in the box and your cursor appears.