Could you tell me how far into your save you are, as when I create a new game without the mod and then reload the game with the mod I can see the research, so I cannot reproduce the problem quickly without knowing your current technologies.
It is a possibility that the research might not have the right pre-requisites, for example the first inventory research requires the base-game toolbelt and chemical science to be researched. If that's the case then you should be able to click on the toolbelt research and see 3 branches below it (inventory research).
