The following table gives an overview of the most important publisher's policies on integrating content into doctoral theses (work in progresss, the table is currently beeing updated).
|Publisher||Policy for cumulative doctoral theses||Source|
|Elsevier||Published PDF can be used within a doctoral thesis and published open access without embargo.|
"Theses and dissertations which contain embedded PJAs as part of the formal submission can be posted publicly by the awarding institution with DOI links back to the formal publications on ScienceDirect."
Usually, Postprint can be published after a 12 months embargo (cf.. Sherpa/Romeo).
Permission to publish articles without embargo can usually be obtained by writing to email@example.com.
In any case, it might be worth checking the publisher's website for regulations or asking the publisher directly.
If you have published with a publisher that completely prohibits re-publishing content within a doctoral thesis, you might be able to buy this usage right from the publisher.
Open acccess dissertations & publishers' prior publiation policies
Many adademic publishers nowaday accept articles for publication, even if they have already been published online as part of an open access dissertation. Similar to how preprints are treated, online disssertations often also do not count as "prior publication" according to many publihers's policies.
See also: Discussion document on best practice for issues around theses publishing (by the Commitee on Publication Ethis)