Some other cool stuff you can do with google is to use quotation marks to find that exact word/phrase. Google searches for words and their alternative meanings or similar other words by default. For example, if you Google ww2 boats, you'll get results with the word "ships" (google will bold it). But if you google ww2 "boats," it will searching specifically for the word "boats," it won't bold similar words.
You can also remove certain words or phrases from your search. Like, you want to search for ww2 ships, but you don't want any battleship results. So, you enter: ww2 ships -battleship. Now none of your results will contain the word "battleship." You can request to find two or more words in the same document. So, if I want to search for ships having to do with Denmark, I could google: ships AND "Denmark." That will display documents with both "ships" + similar words AND the exact word "Denmark." You can do an OR too. Let's say you want to buy either a puppy or a kitten. You can do two google searches to search for breeders specializing in each or you can do something like "puppies and kittens for sale" or "puppies or kittens for sale" or "puppies kittens for sale." This will get you results of documents with documents that have puppies and kittens on them (though, not necessarily all of them as in the case of AND). However, if you write in: puppies OR kittens for sale, you'll get breeders specifying in either. It's like doing two different searches at once.
Also, you can filter by file type. Type in type:file_type, and you'll get results consisting of solely that file type. So if you google: history type:pdf, you'll get a ton of pdfs that have history on them.