From the Results Summary tables it is always possible to drill all the way down to the assay and immunization details.
Suggestions include starting your search very broadly. For example, search for an entire genus [influenza A virus] rather than a specific strain [influenza A virus (A/Puerto Rico/8/34(H1N1))]. This will return 'all data' from which you can pick and choose your desired criteria. This method also helps familiarize you with the fields and their organization.
Also, make use of the Excel spreadsheets [full] downloads in all location. These can be used to combine data (copy and paste) and are filterable for analyzing different combinations of data.