Adding and subtracting search terms, and using quotation marks and wildcards are simple tricks that facilitate casual searching. But Google's search tools let you do much more than that. To view your search options, click Advanced Search on Google's home page. The blue 'Find results' section at the top of the Advanced Search page replicates some of the techniques that are described above. For example, entering your terms in the 'with all of the words' field is the same as a plain Google search. Entering search terms into the 'with the exact phrase' field returns the same results as enclosing your search term in quotes. The 'with at least one of the words' field lets you search for pages containing any of several words, but not necessarily all of them; and the 'without the words' field excludes from the results all pages containing the unwanted terms that you entered.
The search shown in the screen above left finds pages that mention the name 'Einstein' (only about 44 million in all do so) and that contain both the exact phrase "theory of relativity" (this reduces the results to just 1.8 million pages) and either the word "special" or "general" (now we're just under a million pages). This search also excludes pages that mention religion, politics, or philosophy (which gets us down to just over half a million total).
The Google command-line version of the same search is easy to follow; it even appears in the search field that's located at the top of the results page: 'Einstein special OR general "theory of relativity" -religion -politics -philosophy'.
Half a million is still a lot of pages to sift through. Assuming that you speak only English, you can winnow things further by selecting English from the drop-down list on the Language line. But suppose you want to find a good, recently authored, English-language document in PDF file format from an academic source that examines Einstein's thinking about relativity during the decade or so when he published his special and general theories. To the previous search terms, add definition in the 'with all of the words' field; select Only and Adobe Acrobat PDF (.pdf) on the File Format line; choose past 6 months from the drop-down menu on the Date line; enter 1905 and 1916 (the years in which Einstein published his papers on special and general relativity, respectively) on the Numeric Range line; and select Only and type .edu on the Domain line (see the screen above). When you click the Google Search button, wham! Your earlier half-million results have now been narrowed to just 18 documents hosted at Harvard, Princeton, MIT, and other academic institutions.
To perform the same search from the Google command line, type Einstein definition special OR general "theory of relativity" -religion -politics -philosophy site:.edu filetype:pdf 1905..1916. Now let's say you're looking for a PC World article from a few years back that describes the backup software built into Windows XP. You know it came out before Vista's release, and you're pretty sure it was written by some joker named Scott, but you're not sure whether it was Scott Spanbauer or Scott Dunn. Here's the appropriate search command to use: backup software Scott Dunn OR Spanbauer "Windows XP" -Vista site:pcworld.com 2004..2007 filetype:.ht*.
The site: and filetype: operators are only two of many such search helpers that Google supports. For example, if you know that the term you're looking for is part of the page's URL or title (the text that appears in the very top-left of the browser), specify that fact in the Advanced Search page; by default, Google searches for terms in all page elements. Alternatively, to find pages with the words "Denver Broncos" in the page title, but without the words "Oakland Raiders," enter the relevant terms in the 'with all of the words' and 'without the words' fields, respectively. Then select in the title of the page on the 'Occurrences' line, and click the Google Search button. The corresponding command-line search in Google to obtain these results is allintitle: Denver Broncos -Oakland -Raiders.