Current search engines present search results in an ordered list even if semantic technologies are used for analyzing user queries and the document contents. The semantic information that is used during the search result generation mostly remains hidden from the user although it significantly supports users in understanding why search results are considered as relevant for their individual query. The approach presented in this paper utilizes visualization techniques for offering visual feedback about the reasons the results were retrieved. It represents the semantic neighborhood of search results, the relations between results and query terms as well as the relevance of search results and the semantic interpretation of query terms for fostering search result comprehension. It also provides visual feedback for query enhancement. Therefore, not only the search results are visualized but also further information that occurs during the search processing is used to improve the visual presentation and to offer more transparency in search result generation. The results of an evaluation in a real application scenario show that the presented approach considerably supports users in assessment and decision-making tasks and alleviates information seeking in digital semantic knowledge bases.