Perhaps you should try some spelling variations:
clean development » human development, urban development
el communication » cell communication, real communication, 3 communication
development aid » development a, development africa, development agenda
technology et » technology e, technology ecit, technology eimt
relations 2.1 » relations 3.1, relations 1, relations _
et relations » des relations, 3 relations, ethnic relations
costs clean » costs clear
2.1 crisis » 3.1 crisis, 2010 crisis, 2011 crisis
crisis el » crisis _, crisis a, crisis 1

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

• Adding a wildcard symbol may retrieve word variants: technology et relations 2.1 crisis el communication costs clean development aid aortic.*.