The Search function is a fulltext search through a corpus, similar to the well known internet search engines. You can enter one or a few words and the system will give you back a list of articles containing these search string(s). Clicking on one of the results brings you to the articles page.
The options you can set to narrow down the search:
The field "What to search" takes the search string. Below, you can specify in which annotation layer (token, lemma or POS tags) the search will be executed. A value for Fuzziness can specify how exact the search should be - if you are not sure, leave the value by "0". Last not least, you can specify the maximum number of search results you will get back.
With setting the annotation layer to POS, you can search for sentences contain a specific syntactic structure like "ART ADJA NN".