Perhaps you should try some spelling variations:
3.2 communication » 3 communication, 2.3 communication, de communication
developpement de » developpement des, developpement durable
transfer factor » transfer factors, transfer function, transfer history
4 developpement » de developpement, le developpement, et developpement
factor wage » factor water, sector wage, factor case
de afrique » de l'afrique, en afrique, l afrique
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 factor wage race 3.2 communication costs 4 developpement de afrique.*.