Research on the impact of opening-up of China's producer services industry on upgrading of manufacturing export products 并列题名：Research on the impact of opening-up of China's producer services industry on upgrading of manufacturing export products Research on the impact of producer services agglomeration on manufacturing servitization 并列题名：Research on the impact of producer services agglomeration on manufacturing servitization Research on mechanism and countermeasure of China's technical structure on manufacturing export trade Research on the green collaborative evolution of productive service industry and manufacturing industry