If you have to know only one engine to search for technical publications, then I would recommend you CiteSeer. It indexes most of the papers and analyzes their contents in order to give you access to the most relevant ones. A great place to start a bibliography!
Other promising search engines for technical publications are E-LIS, Open Archive for Library and Information Science, Google Scholar and Windows Live Academic. I have not found any advantage in using them - compared to CiteSeer - but they might quickly improve in the near future. So let's give them a chance!