Simple and extended search in Alvin will search in all registered metadata (titles, descriptions, subject words etc.) but not in the scanned document text itself or transcriptions of it.
However, since a large part of Alvin's printed text documents are also published as OCR (object character recognition) -interpreted PDF files, it is possible to some extent to do such searches in search engines that index PDF files, such as for example Google.
Then enter one or more keywords in the Google search box and add the definitions site: www.alvin-portal.org and filetype: pdf to search specifically for PDF files in Alvin.
Example: mynt site: www.alvin-portal.org filetype: pdf
to find texts in Alvin with the keyword "mynt" (Swedish for "coin").
Please note that all PDFs in Alvin are not guaranteed to be indexed in Google.