use WWW;
use DOM::Tiny;
use URI::Encode;

constant URL = 'https://www.ncbi.nlm.nih.gov/pubmed';
my $fh = open :w, 'results5.txt';
constant OUT_FILE = 'results5.txt'.IO;

sub make-term (:$term, :$year) {
    '(' ~ $term ~ '[Title/Abstract] AND united states[pl] AND (("' ~ $year ~ '/01/01"[PDat] : "' ~ $year ~ '/12/31"[PDat])))'
}

my @terms = "list5.txt".IO.lines.map: *.subst(:g, " ", "+").&uri_encode;
my $id = 2135;

for @terms -> $term {
    $id = $id + 1;
    say "Doing searches for $term";
    for 1966..2016 -> $year {
        print "\t...year $year ";
        my $results-num = DOM::Tiny.parse(post URL, term => make-term :$term, :$year)
            .at('meta[name="ncbi_resultcount"]').attr: 'content';
        say "Found $results-num results";
        OUT_FILE.spurt: :append, "$id,$term,$year,$results-num\n";
    }
}