The pos() operator allows you to search for an item within a field by specifying the position in the field. The syntax for this operator is pos(fieldedquery,position,[endposition]). If no endposition is given, then it is assumed to be endposition = position, otherwise this performs a query within the range [position, endposition] where position is the leftmost position considered and endposition is the rightmost. For example:

Example	Results
pos(author:”Oort, J”,2)	papers that have “J. Oort” as the second author
pos(author:”Oort, J”,2,2)	same as above
pos(author:”Oort, J”,1,3)	papers that have “J. Oort” as first, second, or third author
pos(author:”Oort, J”,-1)	papers that have “J. Oort” as the last author, could be only author
pos(author:”Oort, J”,-2,-1)	papers that have “J. Oort” as either of the last two authors
pos(aff:harvard,1)	papers for which the first author has a Harvard affiliation
pos(title:M31,1)	papers for which the title starts with “M31”

Currently the pos() operator works on these fields: author, aff, title.