a. Stem search may expand your search term to include items with a similar linguistic stem, verb tense or meaning. For example a Stem search for 'isolate' will match isolate, isolates, isolated, and other roots of isolate. A Stem search for 'swim' will match swim, swam, swimming, etc.
b. If you aren't sure how to spell a particular name, Soundex search may help you find it based on phonetic spellings or commonly mistyped alternatives. Soundex search for 'basillus' will match bacillus, Smith will match Smythe, and phone will match fone, etc.