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