Which is more correct to say:
1) Scientists are working nowadays to find cures for serious diseases.
2) Scientists work nowadays to find cures for serious diseases.
Both are grammatical and natural and basically mean the same thing.
But you're saying that they've only begun looking for cures recently. Haven't they been doing it for a long time?
I'm not a teacher. I speak American English. I've tutored writing at the University of Southern Maine and have done a good deal of copy editing and writing, occasionally for publication.