Perhaps you should try some spelling variations:
"thi hanh kiem snippets" » "thi khanh kiem snippets", "thi hanh kem snippets", "thi anh kiem snippets", "thi thanh kiem snippets", "thi hanh kiem 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: (((("thi hanh kiem snippets") or ("python using a snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("thi hanh kiem snippets") OR ("python using a snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( thi hanh kiem snippets ) or ( python using a snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("thi hanh kiem snippets") or ("python using a snippets"))) or ("locating bug code snippets"))*.