GeoRef provides access to the geoscience literature of the world. Contains references to over 25,000 sources, including journal articles, books, maps, conference papers, reports, and theses. This database provides abstracts and then links out to the full text, so be sure to use the 'Check for full text availability' button!
Google Scholar can be a helpful search tool as well. A particularly useful feature of Google Scholar is its ability to allow for easily finding articles which have cited an article that you have found.
Step 1: When looking at search results, check for the 'Cited by X' link underneath each result. That will tell you how many subsequent articles have cited this particular article.