Perhaps you should try some spelling variations:
python preprocessing » methods preprocessing, without preprocessing, hol preprocessing
preprocessing real » processing real, preprocessing meta, preprocessing new
reference python » reference method, reference author, reference edition
microarray https » microarrays https, microarray chips, microscopy https
real microarray » al microarray, bead microarray, cell microarray

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: reference python preprocessing real microarray https~.
• Adding a wildcard symbol may retrieve word variants: reference python preprocessing real microarray https*.