Most of the databases and search engines will AND the words of a phrase together. If you wish to search the term as a phrase, put quotation marks around it to refine your search.
One of the easiest ways to refine your search is to use the Boolean operators. The three most common Boolean operators are AND, OR, and NOT, but there are others available.
Most databases use the asterisk * to truncate words. For example, child* will search for the words child or child’s or children. Another example is listed below.
develop* = develop + develops + development + developmental
Google automatically looks for the singular and plural of a word.