Research on the interaction between China's aid, trade and investment in Africa 并列题名：Research on the interaction between China's aid, trade and investment in Africa research on the interaction between juvenile justice and social work research on the relation between foreign trade and employment in China(1978-2005) Research on the interaction between urbanization and industrial transformation and upgrading in China 并列题名：Research on the interaction between urbanization and industrial transformation and upgrading in China research on the internet access, penetration and usage in China