Now is the time when students, and indeed academics, are away from universities. From having academic journal articles at your fingertips, you can find yourself confronted by previously good natured academic publishers persuading you to part with your hard earned cash in order to access an article.
This is not a good thing.
So, from hardest to easiest, here are methods for accessing those articles. This is for the University of Oxford, but other universities have the same setup.
University Library Journal Search
For example http://www.bodleian.ox.ac.uk/ptfl/eresources/ejournals
Various journals have various sign in mechanisms, which is a bit of a pain, but you probably will be able to find what you are looking for here.
VPN
Many journals are accessible when connected within your university – access tends to be based on the IP address of your computer. So, no access from outside. To counter this, you can use a VPN – for example http://help.it.ox.ac.uk/network/vpn/index – you need to download VPN client software, and that should make it seem as though your computer is in Oxford, and you should have access.
Google Scholar
The other way of doing it is to search for the article title in Google Scholar. See for example https://scholar.google.co.uk/scholar?hl=en&q=Agent-Based+Models+and+Behavioral+Operations+Research&btnG=&as_sdt=1%2C5&as_sdtp= . The pdf link on the right should give you access. If that doesn’t work, you can sometimes find the right version by clicking on ‘All n versions’, as one of those may be the pdf.
And if that doesn’t work, just Google the name of the article followed by filetype:pdf, for example https://www.google.co.uk/search?site=&source=hp&q=Agent-Based+Models+and+Behavioral+Operations+Research+filetype%3Apdf&oq=Agent-Based+Models+and+Behavioral+Operations+Research+filetype%3Apdf
Appeal to the Author’s Vanity
And if that all fails, write to the author(s) directly. We are vain people, and there’s nothing better than to receive a request from a student, particularly if they are genuinely interested in the work. Just type their name into Google, and their university webpage should show you their contact email address.