As more and more publishers make their journals available online, there are more and more search utilities which don't connect to one another. Since one step in hunting for relevant literature involves querying indexing services, those of publishers may be especially valuable when they connect to full text of articles. Here's a list of the search utilities I know about, and it's likely that it will continue to grow.

Academic Press IDEAL [more than 175 titles] (click on the SEARCH icon)

Springer [many titles]

Cambridge University Press (free until 1998, but you have to register, and you can search journals one at a time)

Elsevier Press allows you to search but doesn't provide full text. To limit the search to the Trends in... journals follow this slightly hairy procedure: choose AND, use a search like 'pseudomonas AND trends'.