As you say it is your vet/s who offer this advice based on research (assuming peer reviewed and published of course) then they should be able to at least allow you to view the literature whilst in their office. They can't legally provide the entire article unless it is open access, but they can technically provide the abstract which can be used to find out further info, and often contact the author directly with specific questions.
As
@Bradshaw Piggies has already mentioned, many articles published in professional journals are not free to access and you need to buy individual articles, pay to access the entire journal, or check what access rights your institution (academic or professional) can offer you as an employee/student.
But a Google search for scientific articles on a specific topic of interest should bring up plenty of info.
Google Scholar is good as is Research Gate. Or check the big scientific publishers like Elsevier, Wiley, etc.
But if your vet is giving the info then I would suggest they are a good starting place to provide a source for their knowledge.