Perhaps you should try some spelling variations:
voice communication » voice communications, mobile communication, device communication
developing learning » development learning, developing teaching
technologien aids » technologien als, technologien ad, technologien des
formation phase » formation chapter
aids formation » aids information, its formation, ids information
4 developing » 3 developing
costs 4 » costs _, costs a, costs 4.2

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

• Adding a wildcard symbol may retrieve word variants: technologien aids formation phase _ voice communication costs 4 developing learning process.*.