My Girlfriend do not want to spend enough time with me, what should I do?

My Girlfriend do not want to spend enough time with me, what should I do? My girlfriend always spend more time with her family, friends and for studying than with me! We she each other every next day for a few hours, when she is in my city, but usually she is not in my city, for she is studying abroad her master degree! We talk about this issue in our relationship hundred time but she does not want to change her mind about how much time we should spend together! What should I do, I feel very depressed and sad when she is not with me and I want to leave her, for she doing this thing to me, but on the other hand she is a very beautiful and smart girl and I really like her and I do not want to leaver her! Please guys, tell me what should I do?