There are codes that you can use in regular Google to limit your search to only certain domains, like government agencies or nonprofit organizations. Here are some examples.
You'll need to adapt them, for example, swapping in variations in keywords like disease or pandemic for "human health," or other sites like "state.gov" or "nato.int" to get at the international aspects of subjects that you are interested in.
1. Searching a government website:
weather wind site:nga.gov (U.S. National Gallery of Art)
2. Limiting to a non-US government:
art climate change site:.gov.uk
3. Searching Nonprofits:
films about climate change site:.org
If you find the above types of searches helpful, you might be interested in exploring Google Advanced Search, which allows you to target your searches in many different ways. What happens if you limit "filetype:" to .pdf ?
Fun fact: if you ever forget how to get to Google Advanced Search, you can of course... Google it.