I don't think that works anymore, I might be mistaken but I recall trying it and still getting non-word-specific results.
I tried it just now with ' "median" height ' and still got "average" and "mean" results highlighted. (Couldn't reproduce with "expand"/"extend" because I didn't recall the query that produced both.)
The first "result" for me--which heavily focuses on mean--is a Google Snippet, which I imagine could have an unrelated semantics engine and, frankly, too often (I am not saying most of the time, though) shows ridiculous garbage anyway (as it is trying to be more intelligent than computers really can currently pull off).
You probably need to enable verbatim results. Click on the Tools button (below the right end of the search bar) and select "Verbatim" instead of "All results".
I tried it just now with ' "median" height ' and still got "average" and "mean" results highlighted. (Couldn't reproduce with "expand"/"extend" because I didn't recall the query that produced both.)