Can't find certain nodes in Cycles, am I missing something?

I’m trying to make some different materials using nodes under Cycles and I’ve noticed while looking around through these forums and elsewhere that people are using nodes that I just can’t seem to find.

I wish I could remember them all, but there were many… Stucci Texture, Greater Than, Fresnel, Mix Closure etc. etc.

What is it that I am missing?



There are nodes that appear depending on options chosen in the properties panel.