Searching Ebsco Discovery System (the search box on the library home page) for the title often turns up a record for the publication. If it doesn't, the best way to search is to click on the "Advanced Search" link below the search box on the library home page, and then use the Publication Finder link under the Research Tools drop-down menu at the top of the screen.
Type in the title of the journal or magazine you're looking for, in this case: Nature.
Then you will see which years are located in which databases. In many cases, there will be gaps in coverage for some years, and duplication in others.
Each vendor will look different, but most will allow you to browse by issue/date or search within that periodical for keywords or authors.
Finally - we do still retain some bound periodicals in offsite storage that may not be available in online databases. If you're looking for older resources and this doesn't surface them, try searching in Koha, our library catalog, and limiting to Periodicals. Let us know (library@depauw.edu) if you need us to pull any of those volumes!