Perhaps you should try some spelling variations:
population plague » population age, population village, population change
4.2 communication » 4.2 communications, 3.2 communication, 4.1 communication
developpement la » developpement de, developpement et, developpement du
technology city » technology ecit, technology china, technology costs
4 developpement » de developpement, le developpement, et developpement
france 4.2 » france 2.2, france 4.1, france 6.1
la afrique » l afrique, la fabrique, en afrique
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: technology city population plague france 4.2 communication costs 4 developpement la afrique.*.