Perhaps you should try some spelling variations:
"doc hieu sio2 snippets" » "doc hieu so snippets", "toc thieu sio2 snippets", "hoc thieu sio2 snippets", "hoc hien sio2 snippets", "doc hieu sio2 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", "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: (((("doc hieu sio2 snippets") or ("python using a snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("doc hieu sio2 snippets") OR ("python using a snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( doc hieu sio2 snippets ) or ( python using a snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("doc hieu sio2 snippets") or ("python using a snippets"))) or ("locating bug code snippets"))*.