Perhaps you should try some spelling variations:
mobile communications » mobile communication
communications costs » communication costs, communications _
development matters » development patterns, development partners, development centers
clean development » human development, urban development
technology case » technology based, technology can, technology change
case validation » scale validation, cross validation, sample validation
validation de » validation des, validation du, validation set
crise mobile » case mobile, risk mobile, chinese mobile
costs clean » costs clear
matters a » matters _
de crise » de crisis, la crise, de cause

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

• Adding a wildcard symbol may retrieve word variants: technology case validation de crise mobile communications costs clean development matters a.*.