Perhaps you should try some spelling variations:
africa fertilizer » affect fertilizer, rich fertilizer, from fertilizer
fertilizer usage » fertilizer use, fertiliser use, fertilizer type
technical report » technical support, technical experts, technical review
assessment egra » assessment egypt, assessment e6, assessment east
assessment el » assessment e6, assessment esw, assessment 1

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

• If you are trying to use Boolean operators, they must be ALL CAPS: africa fertilizer usage ((assessment el) OR (assessment egra)) technical report.~.
• Adding a wildcard symbol may retrieve word variants: africa fertilizer usage ((assessment el) or (assessment egra)) technical report.*.