For the topic, what are the effects of television violence on children , the main concepts would be television, violence, children. If you search using all lower case letters, the results will include both lower and upper case, but if you search using upper case the results will only include occurrences of that word using upper case, e.g., searching 'tv' will yield occurrences of both tv and TV whereas searching 'TV' will yield only occurrences of that word using upper case. There are essentially three types of tools to use when searching the Web, i.e., subject directories , search engines and meta- search tools. Subject directories are lists of selected Web resources arranged by topic in a hierarchical way. These small databases are compiled by human beings, so are comparatively small, and can sometimes get out of date quickly.
Search results are usually highly relevant, however.
These databases are substantially larger and more current than subject directories. Finding relevant documents can be more difficult, however. Use search engines when looking for specific information, or information on a current topic. Meta-Search Tools allow you to search several tools at one time. They speed up the search process and are useful for searches with unique terms.