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