The folks behind the Google Ngram Viewer have developed a new tools called bookworm. It has a number of corpora (the example above is from bills from beta.congress.gov.) It lets you describe more complex queries and you can upload your own data.
Bookworm is hosted by the Cultural Observatory at Harvard directed by Erez Lieberman Aiden and Jean-Baptiste Michel who were behind the NGgam Viewer. They have recently published a book Uncharted where they talk about different cultural trends they studied using the NGram Viewer. The book is accessible though a bit light.