Perhaps you should try some spelling variations:
le developpement » de developpement, sme development
developpement en » developpement et, developpement des, developpement de
isolation class » isolation can, isolation care, isolation haus
technology 4 » technology _, technology 1, technology 3
4 isolation » _ isolation, 6 isolation, v isolation
do 9.4.1 » iv 9.4.1, ni 9.4.1, up 9.4.1
do 4.1 » dior 4.1

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "technology 4 isolation class ((do 4.1) OR (do 9.4.1)) communication _ le developpement en afrique.~".
• Adding a wildcard symbol may retrieve word variants: technology 4 isolation class ((do 4.1) OR (do 9.4.1)) communication _ le developpement en afrique.*.