Perhaps you should try some spelling variations:
3.3 communication » 2.3 communication, 3.2 communication, 3.5 communication
study population » student population, student populations, city population
developpement la » developpement de, developpement et, developpement du
population case » population based, population age, population change
4 developpement » de developpement, le developpement, et developpement
case france » trade france, marie france, state france
france 3.3 » france 6.1, france 2.2, france 4.1
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 study population case france 3.3 communication costs 4 developpement la afrique.*.