Perhaps you should try some spelling variations:
"dung luan code snippets" » "dung luan cong snippets", "dung luan che snippets", "dung luan de snippets"
"using c core snippets" » "using lc core snippets", "using a core snippets", "using _ core snippets"
"locating bug code snippets" » "locating bung code snippets", "locating bugs code 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: "((((\"using c core snippets\") OR (\"dung luan code snippets\"))) OR (\"locating bug code snippets\"))~".
• Removing quotes may allow a broader search: (((( using c core snippets ) OR ( dung luan code snippets ))) OR ( locating bug code snippets ))~.
• Adding a wildcard symbol may retrieve word variants: (((("using c core snippets") OR ("dung luan code snippets"))) OR ("locating bug code snippets"))*.