Perhaps you should try some spelling variations:
"va trong luan slippery" » "va truong luan slippery", "va tong luan slippery", "va trong quan slippery", "va thong luan slippery", "va tuong luan slippery", "va trong luan slippers"
"python using a snippets" » "python using a slippers"
"locating bug code snippets" » "locating bug code slippers", "locating bung code snippets", "locating bugs code snippets", "locating bug core snippets"

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: "((((\"va trong luan slippery\") OR (\"python using a snippets\"))) OR (\"locating bug code snippets\"))~".
• Removing quotes may allow a broader search: (((( va trong luan slippery ) OR ( python using a snippets ))) OR ( locating bug code snippets ))~.
• Adding a wildcard symbol may retrieve word variants: (((("va trong luan slippery") OR ("python using a snippets"))) OR ("locating bug code snippets"))*.