look through vs roust around in

look through

verb
  • To appear or pretend not to see something or someone who is clearly visible. 

  • Used other than figuratively or idiomatically: see look, through. 

  • To take a view of the contents of; search in, either with the eyes or by hand. 

roust around in

How often have the words look through and roust around in occurred in a corpus of books? (source: Google Ngram Viewer )