How do I search for a keyword or Name in Gmails?

Is there any way I can search my gmail texts for a Name or a keyword?
I use numerous labels, but they only apply to Conversation strings on the whole, and I have many, some 17 or 20 long!
Search with them first and you land up scouring hundreds of gmails, mine going back to 2011. Similarly searching for Sender, or Recipient.

For example: Some time ago someone gave me details about a complicated modification to machine partX. I mentally noted this important fact and carried on with what I was very busy with. Yesterday I spent an hour fruitlessly looking for those details!

I use "EveryThing" v 1.3.4.686(x86) in Win8.1,which is an excellent search facility which can find any name and word containing the same letter combination on my whole C-drive, from Desktop to Registry! but only in Documents or Folders. If I had had the patience to Save those details at the time it would have given them to me in seconds.

Please can you help?
Thanx

Maybe-

Thank you David! First time I've tried that one

Tried it but it has the same disadvantage of only showing those lengthy Conversations you have to tediously read through.
The good thing about Gmail Search is that it DOES highlight the keyword in a relevant gmail