Try to find a survey paper or review article [1] on the field you're interested in. They summarize the current state of the art in a field and link to the relevant papers. If the linked papers are behind a pay wall then you can use arXiv as recommended in another comment by searching the title/authors. The field usually wouldn't be as broad as "databases" but you could probably find one on "distributed wide column stores". I think they're usually published by grad students before they pick their thesis topic.