innovation sustainability 20 Technology: general issues 12 COVID-19 9 sustainable development 9 Humanities 7 Research & information: general 7 climate change 7 education 7 governance 7 urban planning 7 History of engineering & technology 6 Science: general issues 6 health 6 circular economy 5 entrepreneurship 5 resilience 5 technology 5 China 4 Social interaction 4 development 4 higher education 4 information 4 infrastructure 4 machine learning 4 structural equation model 4 sustainable development goals 4 Canada 3 Education 3 Ocean observing 3