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