Perhaps you should try some spelling variations:
reporting bias » reporting biases, reporting bugs, reporting beat
reporting base » reporting based, reporting case, reporting biases
reporting bis » reporting bugs, reporting b, reporting bei

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: "((((reporting bias) OR (reporting bis))) OR (reporting base)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "\"((((reporting bias) OR (reporting bis))) or (reporting base))".
• Removing quotes may allow a broader search: ((((reporting bias) OR (reporting bis))) or (reporting base)).
• Adding a wildcard symbol may retrieve word variants: "((((reporting bias) OR (reporting bis))) or (reporting base))*.