The indexing of cyberspace is a serious issue to which good minds are assiduously applied. Veronica searches, for example, are very good at finding single keywords in gopher indexes and bringing them home. A year and a half ago, I wanted an article by a man named "Franks" and so asked Veronica to find it. Within a minute, there came back about one screen's list of "hits", and when I discarded the ones whose mention of "beans" gave me a culinary suspicion, I found the article in short order. Trying the same search again recently, it now brings in a list nine screens' long (about 150 items). Clearly this kind of searching does not "scale up" and more powerful and discerning tools will have to be found.
But in the meantime, there are strategies that apply well in all kinds of computer searching. Think of the oddest word that defines your search target but is sure to be part of it; or think of a unique combination of words; then ask the question. If it's important that you do a good job of searching the data, think of another way to ask the question and try again -- if searches take seconds, then trying twice is no big deal. If you are still unsure of the quality of your results, be honest with yourself and your readers, but remember that electronic technology is not wholly at fault -- bibliographical searches in the print stacks of a great library are at least as fallible!