This subject comes up A LOT.
Yes, you "can" take a home 120V fixture and "retrofit" it to your camper 12V electrical system. However it WILL require some creativity on your part to do so.
Typically 120V home fixtures will use medium "edison" screw in sockets, not many 12V bulbs are actually made in this style. There are a few but often are 50W incadescent or if you are lucky you can get some 12V CFL bulbs.
To make a home fixture more compatible with 12V you will need to find some 12V replacement or repair bulb sockets which match the 12V bulbs you want to use. Not impossible but may take to looking at car parts places or on the 'net.
Basically remove the 120V edison socket and replace with the 12V bulb socket, you may need to make some brackets and or modify the fixture to hold the 12V bulb socket in place.
Just do be aware that most home fixtures are sized much larger than RV fixtures, this can cause several issues. One is looks, RVs are often very small in scale so a larger light fixture may look nice in the store or home but in a RV may look out of place. So, BEFORE committing to ANY modifications of the fixture it is wise to have someone hold the fixture in place and you look at a distance to make sure it is going to look correct.
Additionally a larger home fixture may hang down lower from the ceiling (and you may have to duck) and often do not have switches (you would need to add a switch if your existing lights have switches).