Perhaps you should try some spelling variations:
clean development » human development, urban development
pt communication » put communication, et communication, post communication
development aid » development a, development africa, development agenda
relations 3.1 » relations 2.1, relations 1, relations _
technology 4 » technology _, technology 1, technology 3
4 relations » 3 relations, 4 relation, 1 relations
costs clean » costs clear
3.1 crisis » 2.1 crisis, 3 crisis, 11 crisis
crisis pt » crisis _, crisis a

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

• Adding a wildcard symbol may retrieve word variants: technology 4 relations 3.1 crisis pt communication costs clean development aid aortic.*.