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