Perhaps you should try some spelling variations:
"python using java snippets" » "python using data snippets"
"viet dung he snippets" » "viet hung he snippets", "viet huong he snippets", "viet trung he snippets", "viet dung cho 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: (((("viet dung he snippets") or ("python using java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("viet dung he snippets") OR ("python using java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( viet dung he snippets ) or ( python using java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("viet dung he snippets") or ("python using java snippets"))) or ("locating bug code snippets"))*.