You will see a search box at the top left of the screen. You can type one or more search terms into this box.
You can search your term(s) in all fields. This is the default option.
Or you can use the pulldown menu labelled Filter directly beneath the search box to search for your term(s) in the title, author, author affiliations, abstract, keyword, DOI, ISBN, ISSN, EISSN, issue, volume, patent assignee, or corporate author field.
Most of the time you will get the best results by using the default all fields.
Note that patent assignee is the person or entity who holds the patent. To filter for patents on a topic, use the filter tickbox for patent under content type.