An electronic journal is just that, the online version of one journal. One database will contain MANY electronic journals. For example, if you want to search just within Ocean Modelling, you will be searching a small part of the database ScienceDirect. You can also search that topic on all of ScienceDirect, and the results from Ocean Modelling will be a subset of the whole.
If you don't know what Electronic Journal you are looking for, click the E-Journals tab above the search box.
From this tab, you have three ways to find a journal. You can search for it using title or ISBN information, you can browse alphabetically by title, or you can browse by subject. When you browse by subject, you will then chose a narrower subject heading, for example, if you chose Physical Sciences and Mathematics, you are presented with these subject headings.
Once you choose a subject heading, you will be shown all the journals that match that subject heading.
If you don't know what databse you are looking for, click the Articles and Databases tab above the search box.
Clicking the box that says Accounting will bring a drop-down subject listing. Chose the subject that best fits your topic, then click search.
This will give you list of the best databases for your subject. Chose the one that seems the most relevant to your topic.