Perhaps you should try some spelling variations:
"den trinh tu snippets" » "den tinh tu snippets", "dan trinh tu snippets", "tien trinh tu snippets", "den trinh ky snippets", "den trinh do snippets", "den trinh tu slippers"
"python using sat snippets" » "python using data snippets", "python using a snippets", "python using raw snippets", "python using sat slippers"
"locating bug code snippets" » "locating bug code slippers", "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: (((("den trinh tu snippets") or ("python using sat snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("den trinh tu snippets") OR ("python using sat snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( den trinh tu snippets ) or ( python using sat snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("den trinh tu snippets") or ("python using sat snippets"))) or ("locating bug code snippets"))*.