Perhaps you should try some spelling variations:
"dong cao cong snippets" » "dong cao code snippets", "duong cao cong snippets", "dong co cong snippets", "dong cho cong snippets", "dong cac cong snippets", "dong cao dang snippets", "dong cua 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: (((("dong cao 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: (((("dong cao cong snippets") OR ("dung java java snippets"))) OR ("locating bug core snippets")).
• Removing quotes may allow a broader search: (((( dong cao cong snippets ) or ( dung java java snippets ))) or ( locating bug core snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dong cao cong snippets") or ("dung java java snippets"))) or ("locating bug core snippets"))*.