I'm assigned to several projects but I don't have a true mentor at work to get constructive feedback from, or to ask questions and learn from. Since I don't have anyone assigned to answer my questions, I have to ask developers assigned to other projects when I have a question I can't answer myself, or for general guidance on how to approach a particular problem.
When I ask, I often get less than helpful answers and the feeling that the other developers can't be bothered to help me, or are just too busy. While I understand that answering these questions aren't a part of their job description, they are the only people at my office I can ask for help. While I don't expect them to take the time to act as my mentor, I would like to increase the chances of getting them to support me when I do need to ask them a question.
How can I ask coworkers for help on projects assigned to me that they aren't involved with when I run in to problems I can't solve alone?