It doesn't mean that God is not available anymore since the Lord Jesus Christ ascended into heaven. The power of the Lord Jesus Christ is still available in the whole world even after Jesus Christ ascended into heaven. We can feel the presence of God everywhere in the world through the power of God which is working in us and throughout all the world.
The Lord our God is ever presence with us. It is because we do not seek after Him with all our hearts that many of us do not see Him. God is seen everyday by those who long after Him. If you need Jesus, you will see Him. When your heart is still after God, God will reveal himself to you. The Bible says that we should seek God while he is near.
There is the time when God is near and there is the time when He is far. God is near to us when we listen to His words and obey His commandments. We must follow this direction if we want to see God in our lives.