Single Letter Searches Are Out
Many search engines let you substitute asterisks for single letters within search phrases, so you could search for "heat*" and find "heated," "heating," and "heats." Google does not support this. However, Google automatically does something very similar each time you search. Google uses stemming technology to find variations of each word in your search, so searching for "diet" automatically finds variations like "dietary" and "diets."
Whole Words Are In
To find a missing word in a phrase, simply substitute an asterisk. For example, Coca-cola was invented by * You can search for phrases with or without quotation marks, but using the quotation marks is often more effective than leaving them off. Quotation marks force Google to find the exact phrase within the quotes, except for the wildcard word.
You can use wildcard words to help complete the phrase when you know almost all the words, such as "The quality of * is not strained," or "A penny * is a penny earned." You can also use searches to find variations of common phrases: "the devil is in the *", or "what a piece of work is *".
Using More Than One Asterisk
You can use as many asterisks in a search phrase as you'd like. "Remember, remember the * of *." You can also use more than one asterisk if you'd like to have more than one wildcard in a row. Just make sure you put a space between each asterisk. "What a * * * is man." Of course the more words you're able to supply in your search phrase, the more likely you are to find what you're searching for. Google is pretty magical, but it can't read minds.