I am searching for the latest developments on an engineering problem. The problem is that the search engines return thousands of pages on the subject, most of which I have read many times.

Is there any way to limit a web search to sites that appeared within the last month?

I found the answer. use Google search, select advanced search when the search displays. There is a dropdown box called "Date, usage rights, numeric range, and more" at the bottom of the search criteria windows.

i didn't see it the first time because I needed to scroll down.