Perhaps you should try some spelling variations:
optimisation problems » optimization problems, optimization problem
program optimisation » program optimization, program optimizations, program reoptimization
progress microarray » protein microarray, probe microarray, proteins microarray
problems progress » problems problems, problems prospects
microarray https » microarrays https, microarray chips, microscopy https

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• Adding a wildcard symbol may retrieve word variants: program optimisation problems progress microarray https*.