There are often multiple ways a subject or topic can be expressed, e.g.,
teen, teens, teenagers, adolescents, adolescence, high school students
or
films, movies, cinema, motion pictures
or
aged, elderly, older people, older adults, senior citizens
Unlike Google and Esearch, most database search tools are 'dumb,' in that if you type in the search term 'aged', the database will display only items that include the word 'aged' but not show items that use other synonyms, such as elderly, older people, etc.
Skim quickly through search results and abstracts looking for synonyms and alternative phrases in order to modify your search and get better results.