Perhaps you should try some spelling variations:
limitation techniques » imputation techniques, mitigation techniques, augmentation techniques
inhalation technique » floatation technique, implantation technique, imputation techniques
tool limitation » food limitation, co limitation, tool orientation
two inhalation » _ inhalation
based two » based co

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( learning-based tool limitation techniques ) or ( learning-based two inhalation technique ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( learning-based tool limitation techniques ) OR ( learning-based two inhalation technique )).
• Adding a wildcard symbol may retrieve word variants: (( learning-based tool limitation techniques ) or ( learning-based two inhalation technique ))*.