Perhaps you should try some spelling variations:
"duong cao cac snippets" » "duong co cac snippets", "duong dao cac snippets", "duong cac cac snippets", "duong cho cac snippets", "duong cao cap snippets", "duong ca cac snippets"
"dung java java snippets" » "dung va java 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: (((("duong cao cac snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("duong cao cac snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( duong cao cac snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("duong cao cac snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.