Sketch Engine
Corpus query tool for studying how words are used in large text collections
Paid
Research Tools
Users search for words and phrases, see collocations, and compare usage across corpora. A word sketch summarizes grammatical patterns for a word. Users can also build corpora from their own texts.
It is a subscription service, with free access for some academic users.
AntConc is a free desktop alternative. Sketch Engine suits linguists and terminologists.