You can get most physics-related materials from regular document delivery sources (see the "Document Delivery Services" entry). Alternatively, check to see if the article is posted free on Cornell's lanl.arXiv.org, and/or use a good search engine to try to find it on another Web site.
To search for articles on a particular topic, by a particular author, etc., use Physics Abstracts. An online version is included in the INSPEC database, available on ProQuest Dialog. A back-up choice would be Scitation or one of the services discussed in the Science and Engineering entry.
If you have a question about everyday physics, Lou Bloomfield at How Everything Works will try to answer it for you. The Argonne National Library host an Ask a Scientist page where you can ask physics questions.