Perhaps you should try some spelling variations:
"coder coder machine placement problem" » "coder coder machines placement problem" (Expand search), "coder coder machine management problem" (Expand search), "coder coder machine elements problem" (Expand search), "coder model machine placement problem" (Expand search), "coder cofee machine placement problem" (Expand search), "coder coffee machine placement problem" (Expand search), "coder decoder machine placement problem" (Expand search), "code code machine placement problem" (Expand search), "decoder codec machine placement problem" (Expand search)
"_ python python python programming" » "_ pythons python python programming" (Expand search), "_ piton python python programming" (Expand search), "_ pitons 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 coder machine placement problem") OR ("_ python python python programming"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"coder coder machine placement problem\") OR (\"_ python python python programming\"))".
• Removing quotes may allow a broader search: (( coder coder machine placement problem ) OR ( _ python python python programming )).
• Adding a wildcard symbol may retrieve word variants: (("coder coder machine placement problem") OR ("_ python python python programming"))*.