I am doing prior art searching. I want to to know whether I need to search for patents which are not yet published. If so, how do I do this?
A related question is: Can I search all patents which are filed today (or less than 18 months ago)?
Patent applications which are not published will not be available for search.
Refer to this link to understand on how to conduct a prior art search: http://www.invntree.com/blogs/how-conduct-patent-search
Patents that aren't yet published aren't searchable unless you're a patent examiner. As an outside searcher, you're limited to issued patents and published applications (in addition to non-patent literature, e.g., everything on the internet).
No, you can't search all patents that were filed today. You have to wait until they are published.
no, patents which are not published are not available for search
At the time of filing you wont be able to search it, best way is to file a patent and do a weekly search with already designed keyword till 20 month you will eventually reach to cover all prior art till filing.