Perhaps you should try some spelling variations:
computation bioinformatics » computational bioinformatics, computing bioinformatics, comparative bioinformatics
bioinformatics tools » bioinformatics https, bioinformatics _, bioinformatics a
database optimized » databases optimizing, database optimising, database limited
tools directional » two directional, cross directional, omni directional
databases invited » databases united, databases induced, datasets invited

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

• If you are trying to use Boolean operators, they must be ALL CAPS: computation bioinformatics tools directional ((database optimized) OR (databases invited))~.
• Adding a wildcard symbol may retrieve word variants: computation bioinformatics tools directional ((database optimized) or (databases invited))*.