It is important to understand a bit about search engines before using them to make very exact queries. Here’s a brief introduction. You might like to add your thoughts in the comments.
Search Engines are the most common means of finding information on the web. They find relevant information by matching keywords or phrases found in (and attributed to) pages on the web.
Search Engines build a database of text retrieved from web pages by automated software programmes called spiders. Spiders are configured to follow links around the web and collect specific information about the pages they find. The Search Engine then builds a database of all this information.
When you use a Search Engine, you are not searching a live interface to the web. You are searching information collected about web pages, saved in a huge database.
There are already billionsof pages on the web and some estimates say that there are up to 7 million pages added every day. It is therefore very unlikely that a search engine will ever index them all. No two search engines will have indexed exactly the same pages. There will be considerable overlap for heavily trafficked sites. So, to access even just 50% of the documents on the web, you need to use a variety of search engines.
Meta Search Engines:
A meta search engine aggregates results from many search engines. e.g.
Meta search tools are worth experimenting with every now and again.
It is worth remembering though that as all search engines do not support the same syntax, their advanced search functionality is very limited.
You might also find it useful to look at this List of Search Engines from Wikipedia. Whatever you’re searching for, rest assured, there is probably a perfect search engine for you.