Biology

* Add quotation marks around phrases to retrieve that exact phrase.
* Add the truncation symbol to the end of root words to retrieve multiple word endings. The truncation symbol for most databases is the asterisk * (for multiple characters -- metho* will retrieve results for method, methods, methodology, etc.) and the question mark ? (for single characters -- wom?n will retrieve results for woman or women).
* Check your spelling, check your search terms and determine if you are using the correct terms recognized by the database.