This paper compares the performance of one thesaurus-based approach against three lexicon-based techniques to the measurement of the crosslingual similarity of domain-specific texts. These methods are applied to an unstructured manually annotated corpus of texts in three languages: French, English and German. We investigate the correlation between these measures and human judgement as well as their ability to detect subtle (in the same topic) and broader (in related topics) differences in comparability. Additional experiments aim to determine the extent to which terminology helps improving measures of similarity in a specialised domain. Results suggest that injecting domain-specific knowledge, when available, is a good alternative to more shallow techniques.