Enhance search basing it on keywords

@stappan I think this was from Ilias (not sure what its github handle is).

> I am wondering if it would be possible to have a more flexible, broad search based on keywords. It seems that I need to add a term exactly as it is in the ontology repository (UBERON) i.e. "ventral root of the sixth lumbar spinal cord segment" to appear on the list. The search function does not recognize what I am looking for to show me any relevant entries if I search for "sixth ventral root" for example even if my search contains all the exact words available in the original ontology term. 

would it be possible to define the priority here? Thanks