To search for theses submitted to other UK institutions, you can use the British Library's EThOS service.
To search for theses submitted to overseas institutions, you can use the ProQuest Dissertations & Theses database, available via LibrarySearch.
This is much like searching for books and other items. You can search for the name of the author and / or the title of the thesis - LibrarySearch will return theses in the search results.
Searching for theses either by thesis type or by subject is not as straightforward.
Firstly, select Advanced Search. From here, change the first search field from Any to Publisher. After that, enter M.D. or Ph.D into the Contains field, depending on whether you are searching for a medical doctoral thesis or a non-medical doctoral thesis. Finally, change Material Type from All Items to Theses.
To search for theses by subject, you can combine the above with an Any Field keyword search.
The search above would find all the PhD theses published by the School of Chemistry, or with the word 'chemistry' anywhere else in the record. You could be more specific and change the Any Field to Title. This would only return PhD theses with 'chemistry' in the title, and not necessarily all PhD theses on the subject of chemistry.
theses.ncl.ac.uk is Newcastle University's digital repository for M.D. and PhD. level theses. Only theses submitted to Newcastle University appear in this repository - theses from other universities are not included.
If you search 'PhD' in the search box at the top of the theses homepage, you can see all the PhD theses produced by Newcastle University that are available electronically. You can then add a filter to search for a word contained in the title.
In the example below, theses with the word 'communication' in the title will be returned in your results. Make sure to toggle the Equals search function to Contains.
To search theses by School, return to the theses homepage. First, click on Newcastle University.
Click on the faculty you would like to search.
Following this, click on the department, institute, or school you'd like to search.
Once you've done this, you'll be able to see the theses that have been produced by a particular school.