Dryer will not dry completely? I have a kenmore dryer that will not dry completley I enjoy...

I have a kenmore dryer that will not dry completley
I enjoy cleaned out the lint filter, hose, vents and I am still have the same problem.
when I start the dryer, the heater/fire lower than the dryer will light and stay on. it will stay hot for a moment or two while but when I come back at the come to an end of the cycle, the cloths are cold and still damp.
what make the dryer stay hot? or shut off the fry prematurely?
not really sure what it is, can someone help?
gratitude
Do you hold to service boilers and gas...
Answers:    The heating item might be going out.
Laminate floor issues?
check the thermostat, it may be an easy fix.