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 de » developpement des, developpement durable
a developpement » au developpement, de developpement, le developpement
technology tax » technology than, technology trap, technology tpm
tax population » farm population, fast 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
de fabrice » die fabrics, avec fabrice, die fabriken
per fig » per firm
costs a » costs _, costs 4

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

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