"The man searches for words."
I think you can also say. buscr palabras as you would say ellos comen manzanas because you mean that they eat apples in general and not the specific apples. I lived for one year in Mexiko and it sounds quite well "buscar palabras".
sarika someone else here recommended this as a way to learn the difference: http://www.spanishnewyork.com/automatic/porpara.php
the hover button suggested 'para' as being correct and then I put para and marked me as incorrect and said I should have used 'por'
it doesn´t works, because ´´search for´´ means only ´´buscar´´ and not ´´buscar por/para´´. entiendes? un saludo!