How to keep my eager heart for professional knowledge

For a long time I have spend on learning of some professional knowledge such as Six Sigma managment system, bussiness management system,mechanical and plastic knowledge and ISO standard management system thereof;as the time goes on I feel that I can not focus on those things maybe there are more and more things needed me to deal with or maybe the eager heart for new knowledge is faded away little by little. Now it is time for me to re-open my mind to receive and learn new things in everyday's working and life,and not just put my heart on one thing;furthermore I should remember that the world is changing from day to day and also the knowledge is updated at second to second.What should I do is just keeping my feet in the road of pursuing the smart knowledge.