When searching for the databases, you can limit your search to the subject of urban schools. For a broad search try using
"Urban Education" OR "Urban Schools" OR "Disadvantaged Schools"
Also look at the subject headings for each database. Use the Thesaurus in ERIC to determine your search terms. Other databases have similar directories. Look at Topics in ProQuest Education Journals, Subjects in the Professional Development Collection, or Subject Guide in Educator's Reference Complete.
Use a truncation symbol, such as ? or *, to find several words with the same root, for example:
child* (finds child, children, and childhood)
behavio?r (finds behavior and behaviour)