Advanced searching in JSTOR allows several strategies that help make your results more specific. These show up in the dropdown menu beside the search boxes ("all fields"), and in check boxes below the search boxes (not shown here) where you may: 

• Limit by type, such as to articles, book reviews, pamphlets and so on.
• By date range, such as within a range of years
• By language
• By a publication's title
• By ISBN (for books and book reviews).

On the screen below these limiters is a list of journals grouped by subject. If you check the boxes to the left of a group or groups, you will limit your search to within these publications, which can be very helpful in a collection this large. The image below shows just the start of the alphabetical list. This list is also available after you have made a search, usually to the left of the results group.