Perhaps you should try some spelling variations:
"coder coder 2d optimization problems" » "coder coder 1d optimization problems" (Expand search), "coder coder and optimization problems" (Expand search), "coder coder cfd optimization problems" (Expand search), "coder decoder 2d optimization problems" (Expand search), "code code 2d optimization problems" (Expand search), "decoder codec 2d optimization problems" (Expand search), "coder encoder 2d optimization problems" (Expand search), "coder code 2 optimization problems" (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 2d optimization problems") OR ("_ python python python programming"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"coder coder 2d optimization problems\") OR (\"_ python python python programming\"))".
• Removing quotes may allow a broader search: (( coder coder 2d optimization problems ) OR ( _ python python python programming )).
• Adding a wildcard symbol may retrieve word variants: (("coder coder 2d optimization problems") OR ("_ python python python programming"))*.