How can I determine which Dialog databases contain the most articles about my search topic?

Within Dialog start a search on the topic of interest across all databases. When the title page is displayed, the narrowing filter "Database" on the right navigation bar - section "Narrow results by" can be used to expand, display and export (click on the link "More options ...") a list of databases with the inherited number of results.

The online display of the database list (click on the link "More options ...") can also be used to exclude databases, which are of no interest or do not have many results. After the selections are being confirmed, any further research will be limited to search the selected databases only.