Supply and Demand

My civilization is way behind all of the other civs both technologically and scientifically. This unfortunate circumstance has caused huge problems for me; from not being able to survive in wars, not being able to expand my territory with cultural influence, and most importantly not being able to trade.
I can't trade technologies with other civs because they all already have what I have, plus ones that I don't. With nothing to offer them, they are unwilling to give me anything in return. In economic terms, there is no demand for what I have to offer. This is because there already exists such a high supply of what I offer. As I have learned from Economics, when there is a surplus of some kind of resource, demand and prices are low, while scarcity results in a higher demand and higher prices because that resource is very difficult to obtain.
Since I am unable to trade with other civs, my civ is unable to advance at the same pace as others. A pretty good comparison can be made between my civ and Papua New Guinea. Both are able to survive on their own, but advancement is nearly impossible because they have almost nothing of value to the rest of the modernized world. Again, no one demands what I have to offer. This also reminds me off the early history between Britain and China, when Britain first traveled to China to obtain valuable spices. Spices were in high demand for the British, but at the same time the British had nothing of value to offer the Chinese. This of course changed when Britain introduced large amounts of opium to China, and the imbalance of trade flipped in the opposite direction. Like Britain, hopefully my civ will be able to find some valuable resource that some other civ demands. It would be really nice if my civ avoided a war like the Opium War, however, because my economy just isn't strong enough to support a large army. The ideal situation is to be able to trade with other civs and maintain long lasting relationships. In this way my economy will be strong and my civ will stay out of global conflicts.