Below are some particularly useful search commands for searching in Google

site

What it does: Searches within a specific site or domain. Useful for locating information from specific government organizations. Also useful for locating materials more generally from .gov or .edu domains. 

Examples: site:who.int or site:.gov

Notes: Be careful if searching for site:.edu. Not all websites that end in .edu are universities or other educational institutions, the domain can be used by anyone. 

Filetype

What it does: Searches for specific file types. Useful for looking for reports, white papers, working papers, or factsheets. 

Examples: filetype:pdf

Notes: There may be information you are missing if you limit to one filetype! 

Additional Examples

Example search: Lyme disease site:who.int filetype:pdf

What it retrieves: This search retrieves pdf files published to the web on the WHO website. 

Example search: bt corn site:usda.gov

What it retrieves: This search retrieves any information on bt corn on the USDA website.