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
developpement la » developpement de, developpement et, developpement du
technology trap » technology trade, technology tax, technology than
trap population » rural population, rapid population, boar population
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

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

• Adding a wildcard symbol may retrieve word variants: technology trap population per fig 2.3.1.1 communication costs _ developpement la fabrice.*.