Ask a librarian if you want special help using any search engine or subject directory. Directories are organized by subject The resources listed really are about those subjects. Subject categories may not match what you are looking for. You decide what terms to use. Each search engine has its own rules for entering the search use their help pages.
Search results have lots of irrelevant links.
HotBot Help pages Metasearch engines send your search to multiple search engines simultaneously and then combine the results a way to search in several places at once.