Codename47

I'm new to this forum but I have a feeling I'll be coming here regularly for a while so... Hi everyone! =) To my question: I'm wondering if there's any rush to hurry and finish as many missions as possible including "key-missions" like Area 51 and similar? I feel I need to research a lot more, I have LOADS of stuff I haven't had the time to finish researching because I've had the feeling of time slipping away. Can I safely "ignore"/dispatch most of the missions to the point where I don't have anything more to research and no more training for my troops? I'm afraid the aliens will sort of "rush ahead" in development if I don't go on all the missions. If anyone understands at all what the hell I'm trying to say here feel free to help a stressed out alien-basher =) See you all around / 47