There's a well known short story that was turned into a movie (Charly) and novel (Flowers for Algernon). In a letter to the doctors who tried an experimental surgery to increase his intelligence. By artificial means, Charlie wrote:
"I recall your once saying to me that an experimental failure or the disproving of a theory was as important to the advancement of learn*ing as a success would be. I know now that this is true. I am sorry, however, that my own contribution to the field must rest upon the ashes of the work of two men I regard so highly."
I, too, think the publishing of negative results is very important.
If you have some free time, read this fictional story. It's one of my favorite pieces of literature.
Flowers for Algernon