When you start searching a database it is a good idea to look first for an Advanced Search link. It will offer you more options to modify your search.
Enter your search terms into the search boxes and use the OR operator to combine synonyms and the AND operator to connect different concepts. Remember to use search techniques such as phrase search, truncation and wild cards, when necessary.
Usually you can target your search words to all fields or to only subject words, abstract or author, for example. Most databases let you choose the appropriate field from the drop-down menu at the end of each search line.
Check the Help in information searching page to find more information about choosing search words and creating a search string!