Perhaps you should try some spelling variations:
"3b model developed countries problems." » "3b model developing countries problems.", "3b code developed countries problems.", "3b mode developer countries problems.", "3b model development countries problems.", "3 model developed countries problems.", "3d model developed countries problems.", "3c model developed countries problems."
"der software development common practices." » "der software development company practices.", "der software development congo practices.", "der software development come practices.", "adept software development common practices.", "free software development common practices.", "a software development common practices."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("der software development common practices.") or ("3b model developed countries problems."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("der software development common practices.") OR ("3b model developed countries problems."))*.
• Removing quotes may allow a broader search: (( der software development common practices. ) or ( 3b model developed countries problems. ))*.