Are you wanting to change the bulb only or the fixture itself?
I would suggest here are tons of places to shop for either, so I just go online as a start as a way to view the full range of options.
If looking for bulb only, knowing what to call the base may be a needed first step. By "screw in" do you mean the type like the normal house light bulb base size? That is often called E26 or E27 and they both seem to fit the same, mmore often sold as E27!
A shop like bulb plus may be a good site to tell you what each sixe base is called but there are lots os styles and sizes so I narrow it down to the correct name first.
Second items to know are what "brightness" and that is in lumens. More light from more lumens.
Color is in Kelvin (K) with duller more like old lights being "redder" at around 3200K and hospital room blue/white at around 5500K!
Personal choice but my older eyes like 5000K for any close work!