Many of the listed documents are subject to copyright, either by their editor or by their publishing journal.
As a reader, you have different options to get the full document. First check on the internet with the Google Scholar link if the document
is restricted or freely available. If this is not the case, check with your academic
institution (school, university) if you can have institutional credentials to download the document on the
Editor's or Journal's official website. Otherwise please consider purchasing the document.