Perhaps you should try some spelling variations:
communication cost » communication costs, communication costa, communications costs
regulation 1.3.3 » regulation 10.1.3, regulation 11.2.3, regulation 11.3.4
ec communication » de communication, 3 communication, 4 communication
technology 1 » technology _
1 regulation » 10 regulation, 15 regulation, 11 regulation
1.3.3 crisis » 13.3 crisis, 13.2 crisis, 2.3.1 crisis
crisis ec » crisis el, crisis en, crisis eu
cost data » test data

You may be able to get more results by adjusting your search query.

• Adding a wildcard symbol may retrieve word variants: technology 1 regulation 1.3.3 crisis ec communication cost data envelopment _ aortic.*.