Keep it simple! Use short, single terms unless your searches are returning too many results.
Use quotes to search for an entire phrase -- e.g., "protein folding".
Except for boolean operators, searches are not case-sensitive, so "Geneva" and "geneva" are equivalent
If you are unsure of the correct spelling, put ~ at the end of your search term -- e.g., cabage~ finds cabbage, steven~ finds Stephen and Stefan (as well as other similar names).