The British Library runs a service called EThOS, which enables individuals to register online at http://ethos.bl.uk and access UK PhD theses. EThOS currently provides details of more than 250,000 theses, many of which are available electronically and can be downloaded from EThOS including all Plymouth PhD theses.
Plymouth theses can also be accessed from PEARL (the university repository) via Primo along with a selection of Masters theses.
If you are a PhD student you can find out about depositing your thesis from our Research Support Libguide
PQDT Open is a source of (mostly) North American theses that have been published as Open Access which complements the British collection held in EThOS.
Theses and dissertations via Primo