PubMed is the free interface for the premier biomedical database, MEDLINE. It was created & is maintained by the National Library of Medicine. PubMed contains both primary & secondary literature. Because it's a free to access, you can use it even when you leave the University of Michigan.
Articles in PubMed are indexed by MeSH (Medical Subject Headings), terms that have specific definitions within the database & help you to create more focused searches.
Enter your search terms, using synonyms, parentheses, & Boolean operators, in the main search bar on the main PubMed window, & click the Search button.
Your results are listed on the Search Results page.
You can see that there are many results, including some that are not related to the question.
Putting dietary intake and food intake in quotation marks will restrict this part of the search to those phrases. The phrases won't map to MeSH terms, but may provide a more focused set of results.
And that's exactly what happens.
Because there are still so many results, add United States to the search:
("dietary intake" OR "food intake") AND (dairy products OR milk OR cheese OR yogurt) AND United States.
What if your search results are not quite what you expected or they seem really off-base? Check Search details, which you can find on the Advanced page. Find the search in your search history, then use the arrow to open the search details window. It shows you how PubMed "translated" your search.
If at least one term for each concept in your search doesn't map to a MeSH term, you should rethink your search terms or contact the library for help.