Final answer:
Search results can indeed be narrowed by file types such as Adobe Acrobat (.pdf), Microsoft Excel (.xls), and Microsoft PowerPoint (.ppt), which is helpful when using databases like Academic OneFile and Academic Search Complete.
Step-by-step explanation:
Yes, it is possible to narrow search results to return results based on specific file types, including Adobe Acrobat (.pdf), Microsoft Excel (.xls), and Microsoft PowerPoint (.ppt). This capability is quite useful when searching databases like Academic OneFile from Gale and Academic Search Complete from EBSCOhost, which provide a wealth of resources including citations, abstracts, and full texts that could be filtered by file format. For instance, Academic OneFile indexes resources in various subjects and offers access to full-text articles in PDF and HTML formats, as well as audio versions in MP3 format. Similarly, databases provided by libraries can often be filtered by the type of document you're looking for, helping to streamline the research process by focusing on the relevant file types needed for your study or inquiry.