This study aims to investigate the query formulation and reformulation patterns such as generalisations, specifications, parallel movements and replacements with synonyms within the search procedure. Results showed that users reformulated their queries by using terms contained in the retrieved results while in the query reformulation process they mainly used terms with parallel meanings. Participants used equally either more specific or more general terms for follow-up queries. Finally, the study revealed that a high proportion of same terms were used instead of unique ones; half of them were included in the Eurovoc thesaurus.