A few tips:
Subject headings are standardized words or phrases, used to describe what the item (e.g. books or articles) is about.
Using subject headings will increase your chance of finding materials that are specific to your topic. Once you have located a resource that is of interest to you, you can sometimes use the subject heading which is assigned to that item to find similar items. On the resource details, this is labeled as "subject."
Examples of subject headings relating to masculinities:
Refer to The Homosaurus, an "international linked data vocabulary of Lesbian, Gay, Bisexual, Transgender, and Queer (LGBTQ) terms" as a companion to subject headings (above) and support your keyword searching (e.g. the main ideas or topic of your search).