The default search mode in PubMed is Basic Search which displays a distinctive single search box. Users may enter one or more search terms and then click the Search button to retrieve results. This is useful in performing a simple and quick search. For example, if you want to run a quick search on the term COVID-10, you may just enter the term or more related terms in the search box to start. While you are entering the search term, the system's auto-complete function displays suggested terms for you. You may choose any of those suggested terms or continue typing your own terms to search. See the screen captures below for a basic search example: