Searches are not case-sensitive. This means a search will include all occurrences of your word, whether capitalized or not. Different forms of words, such as "volcano" and "volcanoes", are considered the same for searching purposes. Accented letters can also be found by typing either the accented or unaccented form: to search for el niño you can type el nino.
If you enter more than one word, pages containing the phrase will be listed first, followed by pages that contain the individual words. You request exact matches only by using quotation marks around the entire phrase, in which case only matches to the phrase will be listed.