The rest of the world totally did have things the Chinese wanted, silver and gold. Not much else at that stage to be fair but China was sucking precious metals from Western Eurasia for most of the first and second millenia.
But the "rest of the world" (meaning mostly the UK in that time period) did have something that was "in demand" in china: opium.
It was the imbalance between imports and exports - china wasn't interested in buying/importing what europeans were selling/exporting - that prompted the uk to start smuggling opium against chinese law, thus paving the way to the opium wars.