Advanced search filters: year range, research domain, open access

[sacredvoid]

Problem

Current filters are limited to country, min citations, and sort order. Users can't narrow results by research domain hierarchy, publication recency, or open access availability — all of which are supported by the OpenAlex API.

Proposed Solution

New Filters

1. Publication Year Range

   • Dual slider or two inputs (from year / to year)
   • Filter authors whose works fall within the range
   • Useful for finding active researchers in a specific era

2. Research Domain / Field / Subfield

   • Hierarchical dropdown following OpenAlex's topic taxonomy: Domain → Field → Subfield
   • E.g., "Physical Sciences → Computer Science → Artificial Intelligence"
   • Can be combined with topic search for precision

3. Open Access Filter

   • Toggle to only show authors with a high percentage of open access publications
   • Uses oa_percent from OpenAlex author data

4. H-index Range

   • Min/max h-index filter
   • Already available in OpenAlex summary stats

Implementation

• Extend SearchFilters type in src/types/index.ts
• Update searchByTopic, searchByName, searchByInstitution in openalex.ts to pass new filter params
• Extend the filter sidebar component in the search page
• Collapsible "Advanced Filters" section to keep UI clean
• All filters reflected in URL query params for shareability

API Support

OpenAlex supports these filters natively:

• from_publication_date / to_publication_date
• topics.domain.id, topics.field.id, topics.subfield.id
• has_orcid, summary_stats.h_index range filters

Priority

Medium — expands power-user capabilities, all backed by existing API support.