Help with Power Query from an online database

Hi YYHoe 

I think I undestand what you ultimately expect to achieve. Hopefully the following will help

Part 1 to 2
Your first query that pulls numbers from i.e. https://pubmed.ncbi.nlm.nih.gov/?term=stress&filter=pubt.clinicaltrial&sort=pubdate returns only 2 fields: [Year] & [# Results] ==> No way to pull the corresponding list of PMIDs

At looked at the construction of the above link and the link to pull PMIDs but couldn't find something consistent enough to auto. construct the second link from the first

Part 2 & 3 - Get keywords for PMIDs
With the URLs you provided at looked at getting the PMIDs and their respective Keyworks from the nested Tables - see attached file

One thing to note regarding the URL for PMIDs. The one you provided is:

https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?db=pubmed&term=stress[tiab]+clinical%20trial[pt]+human[tiab]+extract[tiab]

I also tested:
https://eutils.ncbi.nlm.nih.gov/entrez/eutils/esearch.fcgi?db=pubmed&term=stress[tiab]+clinical%20trial[tiab]+human[tiab]+extract[tiab]

So, same search criteria but [pt] after clinical%20trial in case 1, [tiab] after clinical%20trial in case 2. Results are different:

You'll find the correspoding queries in the attached. Hope this helps a bit