Personal items can be shipped into the country. Depending on the items, there may be a duty/tax assigned through Customs. Because most teachers come into China for a 10-month stay, they do not "import" furniture or items.
A person can purchase almost anything in China. If a person purchases an antique or a piece of registered art, they must have a certificate authenticating the piece and the purchase to produce when going through Customs at exit.
A person cannot export items for re-sale elsewhere, since that constitutes a business and the person would need to have a business license to do so. Many times, if a purchase is made at an art center, the center will package the item and ship it. This takes care of Customs difficulties. Much depends on the size of the purchase.
(State Administration of Foreign Experts Affair October 18, 2006)