Perhaps you should try some spelling variations:
"khoai tang o snippets" » "khoai lang o snippets", "kho tang o snippets", "khoa dang o snippets", "khoai trang o snippets"
"python using java snippets" » "python using data snippets"
"locating bug code snippets" » "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: (((("khoai tang o snippets") or ("python using java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("khoai tang o snippets") OR ("python using java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( khoai tang o snippets ) or ( python using java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("khoai tang o snippets") or ("python using java snippets"))) or ("locating bug code snippets"))*.