For 'any word search':
site:storiesonline.net fighter jet crashed
for phrase search:
site:storiesonline.net "fighter jet crash"
However, keep in mind that Google doesn't see most of what's on SOL. For single part stories, google gets the first 5000 characters of a story. For multi-part stories google see 1 or 5% of chapters.
So, google search is severely limited for storiesonline (and all the sites using the same engine (finestories.com and scifistories.com). So using google you're unlikely to find anything that doesn't fall at the beginning of the story you're looking for.