When searching for conference proceedings try a search using the complete conference title, or a few keywords with the location and year of the conference. You can also search for a specific conference paper if you have its title or author's name.
Most library databases provide the facility to limit by Publication or Document Type, which will allow you to narrow your search to conference papers or proceedings. Look for document types such as Conference Paper, Conference Proceeding, Conference Abstract, Meeting Abstract etc.
Searching the Library databases:
Many library databases index published conference papers and proceedings. Some key multidisclipinary databases that index conference papers/proceedings are listed below:
Many conference proceedings are not indexed in the Library catalogue or databases, but may be freely available, and can be found through a search on Google Scholar.
Unpublished conference papers or proceedings are more difficult to track down. Often the title, author and abstract will be listed in a 'Book of abstracts' included as a supplement of a journal issue, but these don't point you to the full text.
Unpublished papers from a conference may be made freely available on the website of the host organisation, or distributed to attendees only. Some authors make their work available on their own website or via their institution's repository, or you may need to contact the author to request a copy of their paper.
“There are many definitions of grey literature, but it is usually taken to mean literature that is not formally published in sources such as books or journal articles.” Cochrane Handbook - 184.108.40.206 Grey literature databases.