One of the handy things to know about Google searching is to use a minus sign to exclude stuff you don't want, and the plus sign to identify words that you want in the results. While the minus sign to exclude specific words or websites is still active, Google has just dropped the plus sign function.
Google has always tried to return results that include all your search terms, which means that using a plus sign hasn't always make a huge difference. However, it is still useful in situations where Google assumes you meant something else or automatically expands abbreviations.
The alternative is to use quotation marks now. Google has recently expanded the functionality of the quotation marks operator. As well as searching for an exact phrase, you can now add quotation marks to a single word to tell Google to search that word precisely.