It's impossible to acquire a multiple entry visa outside your home country at this time but there's an opportunity this will change in the not too distant future. It allows approved travelers to go to Canada as many times as they want, for as many as ten decades, without needing to re-apply each moment. Duration of stay denotes the maximum quantity of days the holder is allowed to remain in the Mainland of PRC each moment, which is counted from the following day after entry.