If you wish to match a complete phrase, enclose the phrase inside quotes. The exact phrase inside the quotes will be required for a match. The title area searches the actual book titles. The category information is a broad generalization into which a book may fit. The result would be a list of all of the titles published in 1998 in the general category, web.
All searches are case insensitive.
One thing to be aware of is matching sub-strings. If you find undesirable matches, you may exclude them. Sub-string matching will generally work to your advantage. The same is true of exclusions. The last option you have merely limits the display to a certain number on titles.