API that allows for Full Text Search on any Book based on isbn to get the number of results of a word or phrase

I have tried looking at both the Google Books API as well as the Amazon Product Search API to try to find a way to return the number of words matching within a search.

I know that it would be possible to scrape this data as I can easily access this from a webpage, but I do not wish to do a scrape to get this data.

The screenshots below show results for the word "doom", within the book "Masters of Doom", on both Google Books and Amazon.Amazon

I have searched far and wide for a way to do this. I don't care the technology, as long as it is an official API from a company that has access to this data. I will add more details later as to my searching so far:

I have tried a workaround using the custom search API - it doesn't allow for searching on books.google.com (will provide source if needed).

This is not opinion based. I just want a technology that will solve the problem. I just need 1, factual way to accomplish this.