Perhaps you should try some spelling variations:
"dong viet code snippets" » "cong viet code snippets", "dung viet code snippets", "dang viet code snippets", "dong viet co snippets", "dong viet some snippets", "dong viet code slippers"
"python using a snippets" » "python using a slippers"
"locating bug code snippets" » "locating bug code slippers", "locating bung code snippets", "locating bugs code 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 viet code snippets") or ("python using a snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("dong viet code snippets") OR ("python using a snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( dong viet code snippets ) or ( python using a snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dong viet code snippets") or ("python using a snippets"))) or ("locating bug code snippets"))*.