Perhaps you should try some spelling variations:
"coder coder estimation open problems" » "coder model estimation open problems" (Expand search), "coder power estimation open problems" (Expand search), "coder order estimation open problems" (Expand search), "coder coder estimation on problems" (Expand search), "coder coder estimation over problems" (Expand search), "coder coder estimation model problems" (Expand search), "coder decoder estimation open problems" (Expand search), "code code estimation open problems" (Expand search), "decoder codec estimation open problems" (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)

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 estimation open problems") OR ("api python python python programming"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"coder coder estimation open problems\") OR (\"api python python python programming\"))".
• Removing quotes may allow a broader search: (( coder coder estimation open problems ) OR ( api python python python programming )).
• Adding a wildcard symbol may retrieve word variants: (("coder coder estimation open problems") OR ("api python python python programming"))*.