use strict;
use warnings;
use feature 'say';

my $text = do{ local $/; <DATA> };

say $text =~ /Screening Ligands by X-ray crystallography/ ? 'MATCH!': 'NOPE';

__DATA__
 ---------
EFETCH RESULT(1..3): [
1. Methods Mol Biol. 2014;1140:315-23. doi: 10.1007/978-1-4939-0354-2_23.

Screening Ligands by X-ray crystallography.

Davies DR(1).

Author information: <edited for brevity>

##</code><code>##

use strict;
use warnings;
use feature 'say';

my $text = do{ local $/; <DATA> };
my @pmids = $text =~ /PMID:\s+(\d+)/gm;
say for @pmids;

__DATA__
 ---------
EFETCH RESULT(1..3): [
Some title
some author

Author information: 
blah blah blah
PMID: 24590727 

 ---------
EFETCH RESULT(1..3): [
Some title
some author

Author information: 
blah blah blah
PMID: 45867737 

 ---------
EFETCH RESULT(1..3): [
Some title
some author

Author information: 
blah blah blah
PMID: 52497072 

##</code><code>##


##</code><code>##