Google searching can be a useful tool for finding documents that are not indexed in traditional databases, or even GoogleScholar. Leveraging some of Google's advanced searching features can help optimize a search.
Using quotation marks asks Google to locate an exact phrase
For instance: health insurance "policy brief"
This search will only retrieve results that contain the specific phrase "policy brief"
Use the site search function to ask Google to look in a specific site, or a specific kind of site.
For instance: health insurance site:.edu
This query will retrieve results only from sites that have an .edu domain.
You can also perform a site search on a specific website.
For instance: drug costs site:kff.org
This query will look for any mention of drug costs on the Kaiser Family Foundation website
Use the file type search function to ask Google to retrieve a specific kind of file.
For instance: "policy brief" filetype:pdf
This query will only return links to PDFs that mention "policy brief" in the document. Also consider filetype: filetype:doc for Microsoft Word Documents, filetyple:xls for Excel files (which might be useful if you're looking for raw data), or filetype:ppt if you're interested in locating PowerPoint presentation materials.
Google automatically places AND between search terms, but you can use OR to combine queries where either term would be relevant.
For instance: drug OR pharmaceutical
You can exclude terms from your search using the minus sign (-).
For instance: drug -marijuana
This query will retrieve only hits that don't contain the word marijuana.
See Google Search Help for more ways to tailor your queries.
The following collections of resources offer suggested search engines or databases that can be used to look for different types of grey literature: