When you select the professional service you will be challenged for your user name and password. The query form allows you to specify multiple search keywords and to search various other databases as well of the web page database. Try to search for words that are likely to be unique for the subject you are searching for. Here is a sample of the search results. Each entry has a hypertext link to the page found as well as a small amount of text from the page.
Information is sorted according to subject area.
Often the decision as to where in the heirarchy a link belongs is left to the page creator. Yahoo is an example of a heirarchical organization. Note the breakdown into major topic headings. We will select the science section. We will select psychology.