If you are looking for better quality, you can find official episodes on platforms like Disney+ Hotstar (in specific regions like India) or the Official Doraemon YouTube Channel for trailers and shorts.
The original, though short-lived, first attempt at the anime. Doraemon All Episode 3gp Videos
Some community-driven archives and fan forums still host collections of the 1979 classic series in older formats. If you are looking for better quality, you