I'm not completely sure what it is you are asking. as for those verbs paired with the noun "knowledge", you can:
Get Knowledge
Obtain Knowledge
Gain Knowledge
Learn Knowledge (this one sounds odd but is still technically grammatically correct)
Know Knowledge (also sounds a tad odd due to knowledge inherently being something you know)
None of these are idioms as the verbs are being used in their technical fashion.
Hope this helps :)