The problem: no results in PubMed or no useful results in PubMed.
Don’t panic. You could go back to Search Strategy #1. That would be wise.
But you’re short on time & don’t know what to do.
Here’s one strategy.
(1) Search for your terms in the title of an article. The easiest way to do this is to use the [ti] field tag with each term in the search box. Run the search.
(2) Look for an on-target indexed citation. All citations with this tag (highlighted in yellow) are indexed:

Indexed for MEDLINE
Once you’ve located a useful indexed citation, display the citation in the Citation format by changing the Display setting:
Citation Display Option
This display format will show the MeSH terms used to index the citation. MeSH terms describe content. Use them as search terms (do not tag these with the [ti] tag).