Perhaps you should try some spelling variations:
optical communication » optical communications, optic communication, political communication
communication mode » communication model, communication modes, communication module
2.2 information » 4.2 information, 2.2.3 information, 2.2 transformation
development pan » development plan, development plans, development japan
technology 2.2 » technology _, technology 1, technology 3
4 development » 2 development, 4 developing
pan african » pan american, can africa, pan africanism
de optical » _ optical, 3 optical, 12 optical
mode 4 » mode _, mode 1, mode 3

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

• Adding a wildcard symbol may retrieve word variants: technology 2.2 information _ de optical communication mode 4 development pan african.*.