Perhaps you should try some spelling variations:
"dong tan cong snippets" » "dong tan code snippets", "duong tan cong snippets", "dong tai cong snippets", "dong san cong snippets", "dong tan cuong snippets", "dong tran cong snippets", "dong toan 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 tan 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 tan cong snippets") OR ("dung java java snippets"))) OR ("locating bug core snippets")).
• Removing quotes may allow a broader search: (((( dong tan cong snippets ) or ( dung java java snippets ))) or ( locating bug core snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dong tan cong snippets") or ("dung java java snippets"))) or ("locating bug core snippets"))*.