用真实用户数据持续评估学术搜索推荐策略，发现语义相似性最有效。

Delivering relevant recommendations in academic search engines is a complex task due to the diversity of subject areas, information types, and user preferences. In this case study, we address these challenges by integrating and evaluating a range of recommendation systems within GESIS Search - a domain-specific search engine for the social sciences that provides researchers with access to research data, publications, variables, and measurement instruments. To support continuous, real-time evaluation of multiple recommendation strategies with actual platform users, we utilize the STELLA evaluation framework. We implement and compare a diverse set of algorithms, including traditional lexical similarity, semantic document similarity by using transformer-based embeddings, and session-based recommendations based on click paths from historical user sessions. Our results show that users prefer recommendations based on semantic similarity, which outperformed term-similarity and session-based methods. However, the performance of recommenders varies across categories within GESIS Search, suggesting that information-seeking behavior differs by information type. Overall, our study provides insights into how continuous evaluation can be incorporated to develop recommendations that better align with the preferences in academic search portals.