Your query is expanded to search all the databases you choose. Long queries result in very long expanded queries, which are truncated by either Verity or the Web server. If this happens, try the Fielded Search or the Expert Search and target only the fields you want to search. Date fields will not be searched. Use Fielded search or Expert Search for date searching.
More operators are available in the Expert Search.
Your expanded query shows up on the top of the results page. You could save favorite Expert Search queries in a text file, keeping them available for future use. Similar words have characters inserted, deleted, or transposed. The more instances of these words in a page, the higher it appears in the results list. NIH Enclose terms in double quotation marks if you want the search engine to take them literally .