Perhaps you should try some spelling variations:
"coder coder concrete control problems" » "coder coder concreto controle problems" (Expand search), "coder coder discrete control problems" (Expand search), "coder coder concentrate control problems" (Expand search), "coder coder concrete control program" (Expand search), "coder powder concrete control problems" (Expand search), "coder core concrete control problems" (Expand search), "coder model concrete control problems" (Expand search), "coder decoder concrete control problems" (Expand search), "code code concrete control problems" (Expand search), "decoder codec concrete control problems" (Expand search)
"on python python python programming" » "on pythons python python programming" (Expand search), "on piton python python programming" (Expand search), "on pitons python python programming" (Expand search), "in python pythin python programming" (Expand search), "of python pythof python programming" (Expand search), "_ python pyth_ 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 concrete control problems") OR ("on python python python programming"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"coder coder concrete control problems\") OR (\"on python python python programming\"))".
• Removing quotes may allow a broader search: (( coder coder concrete control problems ) OR ( on python python python programming )).
• Adding a wildcard symbol may retrieve word variants: (("coder coder concrete control problems") OR ("on python python python programming"))*.