I know "research works" does not make sense. (I think I heard "works" is only used for art pieces.)
The problem is that I want to use "research work" to indicate multiple research articles. Can I simply assume it’s a collective noun and make a sentence like this?
The early research work focus on …
Yes and No
Early research work focused on….
"The" may or may not be correct dependent on context.
“Works” has a different meaning. It is used to describe construction or engineering projects.
There are traffic jams all over the city due to the road works in the centre.
Works on the bridge were delayed by 4 weeks due to bad weather.
The Works were signed off 6 months after the Completion Date.
So you should never use “works” to describe the work you do when you’re sitting at a desk.