Perhaps you should try some spelling variations:
"van khanh sio2 snippets" » "van khanh son snippets", "van thanh sio2 snippets", "van hanh sio2 snippets", "van anh sio2 snippets", "van khanh 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: (((("van khanh 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: (((("van khanh sio2 snippets") OR ("python using a snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( van khanh sio2 snippets ) or ( python using a snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("van khanh sio2 snippets") or ("python using a snippets"))) or ("locating bug code snippets"))*.