To get Panda Research you must complete the Breeding Giant Pandas scenario. You need to breed Giant Pandas, but you cannot get them until you make fifteen excellent exhibits. You also need to do all Panda Research and get their cave and bamboo. You can then get only two pandas, one male and female. To raise your chance of breeding your pandas, build their exhibit, pause game play, then buy as many pandas as needed before resuming the game. After that, wait until the scenario ends.