The Open Access Initiative is a program, which provides free access to scientific documents. It's goal is to have peer-reviewed articles, which were published in journals that provide open access publishing, available freely to anyone and anywhere on the world.
The most common kinds of open access articles:
Fully gold - those articles, which were published in journals, that provide open access publishing only. The cost of the publishing of these articles is paid by the author.
Hybrid gold - those articles, which were published in journals, that can be subscribed for, so mainly they contain not open access content. In these cases, paying for the open access publishing will make these articles freely available on the publisher's website for anyone.
Green - In many cases the authors are able to upload their publications into a repository of some kind, provided they abide the rules of the contracts of the authors and publishers. This is called self-archiving. In the case of the Semmelweis University, uploading to our repository can be done through the MTMT (Hungarian Scientific Publication Database) database.
More information about journal policies on open access publishing can be found in the Sherpa-Romeo database http://www.sherpa.ac.uk/romeo/ The database can be searched for journals and publishers. These information are for only a general guideline, the exact policies can be alwasy found on the publisher's website.
More information and resources:
Directory of Open Access Journals (DOAJ): http://doaj.org/
Semmelweis University journal catalog: http://lib.semmelweis.hu/nav/folyoirat_katalogus
Budapest Open Access Initiative (BOAJ) http://www.budapestopenaccessinitiative.org/read
Open Society Institute: http://www.opensocietyfoundations.org/
Registry of Open Access Repositories Mandatory Archiving Policies (ROARMAP) http://roarmap.eprints.org/
Hungarian Open Access journals: http://www.open-access.hu/magyar_oa_folyoiratok
Open Archives Initiative http://www.openarchives.org/
Berlin Declaration: https://openaccess.mpg.de/Berlin-Declaration