Perhaps you should try some spelling variations:
"coder precoder sphere theory problem" » "coder precoder scheme theory problem" (Expand search), "coder decoder sphere theory problem" (Expand search), "coder precoder sphere theory problems" (Expand search), "coder precoder sphere the problem" (Expand search), "coder precoder sphere theory program" (Expand search), "coder precoder pure theory problem" (Expand search)
"api python python python programming" » "api pythons python python programming" (Expand search), "api piton python python programming" (Expand search), "api pitons python python programming" (Expand search), "rpa python python python programming" (Expand search), "manim python python python programming" (Expand search)

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("coder precoder sphere theory problem") OR ("api python python python programming"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"coder precoder sphere theory problem\") OR (\"api python python python programming\"))".
• Removing quotes may allow a broader search: (( coder precoder sphere theory problem ) OR ( api python python python programming )).
• Adding a wildcard symbol may retrieve word variants: (("coder precoder sphere theory problem") OR ("api python python python programming"))*.