Perhaps you should try some spelling variations:
population center » population census, population censuses, population change
2.1 communication » 2.14 communication, 2.3 communication, 2.7 communication
technology set » technology sector, technology 1, technology 2.2
set population » meet population, de population, em population
center prices » center prcec, center parties, center protest
4 developing » 3 developing
developing a » developing _
prices 2.1 » prices 2.4, prices 2.3, prices 3.1
a afrique » l afrique, 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 set population center prices 2.1 communication costs 4 developing a afrique.*.