Perhaps you should try some spelling variations:
"tung van cong snippets" » "tung van code snippets", "trung van cong snippets", "tang van cong snippets", "dung van cong snippets", "tung van dong snippets", "tung van phong snippets", "tung phan cong snippets"
"locating bug core snippets" » "locating bug code snippets"
"dung java java snippets" » "dung va java 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: (((("tung van cong snippets") or ("dung java java snippets"))) or ("locating bug core snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("tung van cong snippets") OR ("dung java java snippets"))) OR ("locating bug core snippets")).
• Removing quotes may allow a broader search: (((( tung van cong snippets ) or ( dung java java snippets ))) or ( locating bug core snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("tung van cong snippets") or ("dung java java snippets"))) or ("locating bug core snippets"))*.