Can I filter the search results by Education Level, Audience, Resource Type, Access Rights, etc.?
Yes. Education Level, Resource Type, Access Rights, Language, Medium, and MimeType are fixed controlled vocabularies that are normalized in the NSDL DC metadata and search index. Subject also has a controlled vocabulary but the metadata is not filtered so there are other subject vocabularies and keyword that appear in that field. Use the ListTerms API request to fetch the list of terms for each field (to get a list of fields, use ListFields). For example, these requests list the terms/vocabs for Education Level and Type, respectively: http://nsdl.org/dds-search?verb=ListTerms&field=/key//nsdl_dc/educationLevel http://nsdl.org/dds-search?verb=ListTerms&field=/key//nsdl_dc/type Fields that start with /key//nsdl_dc/ correspond to metadata the elements in the NSDL DC metadata framework, which represents the educational resources in the library. See this NSDL DC metadata guide for details.
