Perhaps you should try some spelling variations:
reference python » reference method, reference author, reference edition
microarray cross » microarray probes, microarray chips, microarray post
python progress » python programs, method progress, python program
case microarray » based microarray, cancer microarray, course microarray
progress case » programs case, progress a, progress part

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 progress case microarray cross~.
• Adding a wildcard symbol may retrieve word variants: reference python progress case microarray cross*.