Every database and index offers a way to search for works written by a particular author. Usually it's a fairly straightforward process. The database should either have an input box marked "author", or a generic input box and a way to limit the search to the "author" field.
Most modern scientific articles have multiple authors - sometimes a whole lot of them - and all get equal billing in index databases. Accepted practice in chemistry* is usually that the first listed author is the one who did most of the work and writing; other authors are listed in declining order of contribution. In academic chemistry labs, the last author position is usually reserved for the supervising professor who has the grants and runs the lab (known as the Principal Investigator, or PI).
* The question of authorship is subject to much debate and variation across disciplines. An interesting study on this question can be found in PLOS One.