The most reliable way to find out if a journal is available online is the Journals A to Z.
Hit a paywall?
Always follow the 'find it @ WACHS' button to get past paywalls. If you start from a Library link to free sources such as PubMed you'll find the button on the abstract view of the record. In GoogleScholar click on >> that appears under the citation to see the 'find it @ WACHS' link.
There are other solutions, including bookmarklets and the LibKey Nomad browser extension that can link you to subscribed full text even if you have not accessed the reference from a library link.
Links to resources that require a subscription have to carry through the Library's authentication to the publisher.
For example, you want this paper: Individual care plans reduce falls and broken hips in New Zealand hospitals - BMJ 2016. The article link is https://doi.org/10.1136/bmj.i6490but this will not allow you full text access. You need to add the library prefix string to the link https://login.wachslibresources.health.wa.gov.au/login?url=https://doi.org/10.1136/bmj.i6490
The prefix is - https://login.wachslibresources.health.wa.gov.au/login?url=
You can copy and paste the prefix to articles links but that is tedious - it is easier to add it with one click using a bookmarklet, or the LibKey Nomad browser extension.
Sometimes you will have to go back to the library's Journals A-Z as the library's subscribed access may not be via the site you are on. For example, links to paywalled articles in https://www.thelancet.com/ will not work because the library's access to The Lancet is via ClinicalKey https://login.wachslibresources.health.wa.gov.au/login?url=https://www.clinicalkey.com.au/dura/browse/journalIssue/01406736/
Lookup a journal article by DOI or PMID
Type or paste a DOI name, e.g. 10.1093/infdis/jiaa429 into the text box below.
Be sure to enter all of the characters before and after the slash.
Do not include extra characters, or sentence punctuation marks.