Perhaps you should try some spelling variations:
"using luoc cong snippets" » "using low cong snippets", "using lc cong snippets", "using nuoc cong snippets", "using luc cong snippets", "using quoc cong snippets"
"dung java java snippets" » "dung va java snippets"
"locating bug code snippets" » "locating bung code snippets", "locating bugs code snippets", "locating bug core snippets"

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (((("using luoc cong snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("using luoc cong snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( using luoc cong snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("using luoc cong snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.