If you’d like to know how to tell for biological or medical articles...
First, nih.gov is open-access. They have full papers like the one you link to at “PubMed Central.” For other papers on biology or medicine, the journal’s page usually has a link to “PubMed” (not Central) which contains the abstract and citation. (for this paper, here). If the paper is not open-access, PubMed is usually a better link than the journal website.
At the upper right, the PubMed entry has an icon for the journal’s website, which is a link to article at the journal’s site. The icon tells you whether the publisher makes it free (by including to word “free” or not). There may be other icons, if the paper is available in other places. Thus, this article has two icons: a non-free Science link and a free PubMed Central link.
Outside of biology, it’s more journal-by-journal, but it’s tricky to tell. Google Scholar is a good way to search for alternate sources, if you don’t have university access.
If you’d like to know how to tell for biological or medical articles...
First, nih.gov is open-access. They have full papers like the one you link to at “PubMed Central.” For other papers on biology or medicine, the journal’s page usually has a link to “PubMed” (not Central) which contains the abstract and citation. (for this paper, here). If the paper is not open-access, PubMed is usually a better link than the journal website.
At the upper right, the PubMed entry has an icon for the journal’s website, which is a link to article at the journal’s site. The icon tells you whether the publisher makes it free (by including to word “free” or not). There may be other icons, if the paper is available in other places. Thus, this article has two icons: a non-free Science link and a free PubMed Central link.
Outside of biology, it’s more journal-by-journal, but it’s tricky to tell.
Google Scholar is a good way to search for alternate sources, if you don’t have university access.
Cool, thanks!