If you search standard Google for medical or scientific topics, the results you get will contain more than just journal articles. You will also find news articles, social media posts and personal blogs, along with other types of content that might not be very reliable. (Not sure if you can trust a Google source? Take the CRAAP test: https://researchguides.ben.edu/source-evaluation)
Google Scholar is a special type of Google search engine that looks only for journal articles and other, similar sources.
To access Google Scholar, search for it in Google, or click the link below:
Type your concepts or terms into the Google Scholar search box. Don't worry about combining concepts with AND or enclosing phrases in quotiation marks. Google Scholar is fairly good at identifying different concepts, and linking words as phrases (it's also good at finding different word endings, so you generally don't need to truncate search terms).
Screenshot of the Google Scholar search box, with search terms entered
Like regular Google, Google Scholar may return huge numbers (millions!) of results. Just look through the first few pages of results, as they are likely to be the most relevant, or you can view results from particular years.
Links to journal and publisher websites will appear beside some results. Try clicking on these to see if they connect you to the free full text. Unfortunately, not all Google Scholar results will be available for you to read or download, because they may be published in premium rather than open access journals.
Screenshot of a Google Scholar results page, with link to journal/publisher website highlighted
Screenshot of a free, open access article available via Google Scholar