help oneself vs look up

help oneself

verb
  • Used other than figuratively or idiomatically: see help. 

  • To serve oneself, especially to take food or other supplies, rather than wait to be served by another; used to indicate friendly permission or invitation. 

  • To exhibit self-control. 

  • To take something freely; to serve oneself without restraint. 

look up

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

  • To reconnect or meet with someone that one used to know. 

  • To obtain information about something from a reference book. 

  • To have better prospects. 

  • To enter a query into a database or search engine. 

  • To obtain, or seek to obtain, information about something. 

How often have the words help oneself and look up occurred in a corpus of books? (source: Google Ngram Viewer )