Perhaps you should try some spelling variations:
"competitive requirements hop history" » "competence requirements hop history", "composition requirements hop history", "competitive procurement hop history", "competitive requirements how history", "competitive requirements ap history", "competitive requirements from history", "competitive requirements conn history", "competitive requirements deep history"
"comparative management practice theory" » "compensation management practice theory", "comparative management practices theory"

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: (("comparative management practice theory") OR ("competitive requirements hop history"))~.
• Removing quotes may allow a broader search: (( comparative management practice theory ) or ( competitive requirements hop history ))~.
• Adding a wildcard symbol may retrieve word variants: (("comparative management practice theory") or ("competitive requirements hop history"))*.