General Rules for Searching:
Keywords - if you're not finding what you're searching for, try another keyword.
Concepts - Identify the concepts that you'll want to search, more broadly such as Culture, Social, Politics of the setting in which the art was created.
Concepts more specific to the object could include the art movement for example Surrealism, and then subsets of Culture, Society and Politics, such as Gender, Labor, Social Class, Warfare, Feminism, etc.
Sources - No one database has everything - for this research project, you'll likely want to try several COD Library sources, such as the Library Catalog, JSTOR, Oxford Art Online, and Academic Search Ultimate.