You can use an asterisk (*) or a question mark (?). The difference is that an asterisk can mean one or more characters, whereas a question mark means one character.
Examples:
n*d will match any word that starts with 'n' and ends with 'd'.
n?d will match any three letter word that begins with 'n' and ends with 'd'.
You can also search by phrase, but they must be placed in quotes... e.g., "To be, or not to be." It is worth noting that punctuation is completely ignored, so the comma and period in the above phrase would be ignored.
In addition, we have thoughtfully provided a series of logical operators. For example, you could search for childrens' games by specifying:
game and children
Or you could search for non-violent childrens' games: