Perhaps you should try some spelling variations:
"coder and variable diffusivity problem" » "coder and variable diffusion problem" (Expand search), "coder and variable diffusivity from" (Expand search), "coder _ variable diffusivity problem" (Expand search), "code and variable diffusivity problem" (Expand search), "codes and variable diffusivity problem" (Expand search), "poder and variable diffusivity problem" (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), "rpa python python python programming" (Expand search)

You may be able to get more results by adjusting your search query.

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