What could you take back?

I recently found out that mankind didn't really begin to understand how reproduction worked until about 130 years ago (Oscar Hertwig in 1876). It is astounding to me that relatively recently scientists didn't understand the roles of eggs and sperm. The whole idea got me thinking along the lines of time travel and how much impact someone could have if it were possible.

That line of thought got me thinking: what could I bring back? If I woke up tomorrow in 1800 with just myself and clothes, how much technology could I bring from memory? How much do I really know about science basics? Enough to dramatically influence scientific progress? I could tell the world that sperms and eggs fuze to form a zygote, I could explain how transistors work, or I could talk about bacteria killing fungi.... but I don't know that I could actually produce anything tangible without reference books or modern tools. I could probably make a windmill capable of electricity generation, but I doubt I'd have the skill to make anything useful to use the power it generated.

I realize that it's a sort of silly thing to think about, but it does make you realize that even if you are really smart in today's terms, you still depend on society at large to provide you with most of what you need to get anything done. All that said, if you were successful you'd probably get labeled as a witch or something anyway. Silly line of thought, but sort of a neat scenario to walk yourself through.