Web of Science is an easy to use database with lots of filters and an easy to read layout.
Looking at the images below, a simple search for a single term (immunology) returns more than half a million results. These results can be refined by creating a more specific search string, adding search terms, or using the filters.
The image below shows the record for a single article. At the top of the page there are several different ways to access the article including the "Get it at UC" button. Web of Science will show you all of the keywords associated with each article on this page. This can be helpful if you find an article strongly related to your research interests. You might consider adding some of these keywords to your search string.