Unlike a library, the Internet has no handy catalog, and search engines are not objective searchers. Each has its own system of locating material, categorizing it, and establishing the sequence for reporting results. One search site, patterned on a library index, might be selective. Another might separate advertising from search results, while a third pops up “sponsors” that pay advertising fees first, even though sites listed later might be better matches.
The best search engine is one you select and learn to use well. If you have a favorite, check its search practices. As you work out a combination of search terms relevant to your research question, think of your wording as a zoom lens. Tinker with it to search as narrowly as possible, finding relevant sites but avoiding endless options. Then try the identical search with another search engine to compare the results.
Comparing Search Engine Results