Some document databases allow you to use EOS, EOP, EOG search operators. These operators allow a document database user to run a search that will find where multiple strings appear within a set number of sentences, paragraphs, or pages of one another. So, for example a search structured this way:
New York W/3/EOP mortgage
. . . will find documents where 'New York' appears within three paragraphs of 'mortgage'.
The EPA's National Service Center for Environmental Publications Repository is one example of a database in which you can use these search operators. Here we see an example of a search for two phrases within 8 sentences of one another:
The ZyLAB eDiscovery platform, allows you to use these search operators.