glean vs obtain

glean

verb
  • To frugally accumulate resources from low-yield contexts. 

  • To collect what is left behind (grain, grapes, etc.) after the main harvest or gathering. 

  • To gather information in small amounts, with implied difficulty, bit by bit. 

  • To gather what is left in (a field or vineyard). 

noun
  • A collection made by gleaning. 

obtain

verb
  • To get hold of; to gain possession of, to procure; to acquire, in any way. 

How often have the words glean and obtain occurred in a corpus of books? (source: Google Ngram Viewer )