This paper describes the use of GrETEL for linguistic research. GrETEL is a linguistic search tool that enables users to look up constructions in syntactically annotated corpora or <i>treebanks</i>. It provides online access to the data, allowing users to query a treebank using either an example sentence or an XPath expression in order to look for similar constructions. A major asset of GrETEL is that it enables non-technical users to consult treebanks in a user-friendly way, which is also in line with the main CLARIN goal of applying the results of speech and language technology to research in the humanities and the social sciences. Besides a description of the querying procedure in GrETEL, this paper presents a selection of research in Dutch syntax and semantics that has been carried out using GrETEL. Furthermore, an overview is given of further developments.