Perhaps you should try some spelling variations:
3.2 communication » 3 communication, 2.3 communication, de communication
developpement en » developpement et, developpement des, developpement de
transfer sector » transfer factor, transport sector, transfer factors
4 developpement » de developpement, le developpement, et developpement
sector wage » sector wages
wage race » wages race, wage rate, age race
race 3.2 » race 3.7, race 4.2, rice 3.2
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 transfer sector wage race 3.2 communication costs 4 developpement en afrique.*.