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