Perhaps you should try some spelling variations:
communications costs » communication costs, communications _
2.1 communications » 3.1 communications, 4.1 communication, 1.1 communication
estimation under » estimation model, estimation de, estimation using
a developpement » au developpement, de developpement, le developpement
developpement l » developpement il, developpement la, developpement de
technology gap » technology 1, technology 2.2, technology 3
gap estimation » naep estimation, 2a estimation, gls estimation
under rice » under rise, under river, under risk
l afrique » en afrique
rice 2.1 » rice 3.1, rice 4.1, rice 1
costs a » costs _, costs 4

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

• Adding a wildcard symbol may retrieve word variants: technology gap estimation under rice 2.1 communications costs a developpement l afrique.*.