An international science and technology center is like a big lab where scientists and engineers from different countries work together to find new and cool things. It's a place where people from different countries can share their ideas and work together to solve problems that are too big for just one country to solve on their own.
Imagine you and your friends are trying to build a big sandcastle, but you don't have enough buckets or shovels. So you invite some kids from other neighborhoods who have buckets and shovels to join in, and together you can build an even bigger and better sandcastle than you could have done alone.
That's basically what an international science and technology center does, but with really smart grown-up scientists instead of little kids building sandcastles. They can collaborate on all kinds of science and technology projects, like finding ways to make medicines work better or figuring out how to make cars that run on electricity instead of gas.
And once they figure out something cool, they can share it with other countries to help make the world a better place for everyone.