Here's how. You simply have to type the following in the Google search window:
search term site:URL
Don't leave a space after the colon.
For example, let's say you wanted to find all the past posts on this blog, The Daily Beat, where I've reviewed a book or a movie. If you type the following in a Google search window, you will see that it returns only posts from The Daily Beat that include the word "Review."
When have I mentioned the word "zombie" on The Daily Beat? To find out, type the following in a Google search window:]
To search my blog for posts with the word "pirate," type the following in a Google search window:
Ninja would look like this: