1) Diligently 2) Heavily 3) In a laborious manner 4) Logically 5) Meticulously 6) Painstakingly 7) Pedantically 8) Slowly 9) Tediously 10) Thoroughly 11) Unimaginatively 12) With difficulty 
[adv] - in a laborious manner
laboriously 1. With great expenditure of effort, or in a manner requiring much work. 2. With labor, toil, or difficulty.
adverb in a laborious manner; `their lives were spent in committee making decisions for others to execute on the basis of data laboriously gathered for them`