for (let i = 0; i < rowscount; i++){
              $.getJSON(
      "https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?db=pubmed&retmode=json&retmax=500&term=" +
      terms,
      function (data) {
        var pmids = data.esearchresult.idlist;
        var pmidlist = pmids.join();
        pmid_List.push(pmidlist);
        if (i == rowscount - 1) {
          // call the related function
        }
      });
       }