Duplicate keyword problem

Hi everyone,

I have a trouble with Elastic search. Let's say I have about 1 millions articles. Within them, there are about 100k articles talk about Corona virus. The thing is when lecturers and students search for "corona" as a keyword elastic search almost return the articles that have the keyword "corona" as many as possible and put the latest article to the bottom of search result.

Here is an example:

I created an article today that contain the keyword "corona" just 1 time and in the database there is another article created 3 months ago that has the keyword repeated about 100 times.

If I use elastic search match string then it will list the old article as more matched that the one I created today. however, all that I want is to prioritize the one I created today.

In the end I would like ES to treat the number of appearance of keywords the same. in this case Corora keyword appear 1 times or N time is the same. So that I can bring the latest article ontop of search result.

Could anyone help me to resolve this? Thank you