Perhaps you should try some spelling variations:
2.3.1.1 communication » 2.2.5.4 communication, 3.4.1 communication, 6.2.4.1 communication
technology trade » technology trends, technology transfer, technology transfers
trade population » create population, france population, age population
developpement la » developpement de, developpement et, developpement du
4 developpement » de developpement, le developpement, et developpement
population per » population panel, population p230, population area
fig 2.3.1.1 » fig 2.3.1.2, fig 2.3.1.3, fig 2.3.1.4
la fabrice » la fabrique, la matrice, la farce
per fig » per firm
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 trade population per fig 2.3.1.1 communication costs 4 developpement la fabrice.*.