Perhaps you should try some spelling variations:
"duong van chan snippets" » "duong va chan snippets", "luong va chan snippets", "dang van chan snippets", "duong van chat snippets", "duong dan chan snippets", "duong van phan 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 van chan 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 van chan snippets") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( duong van chan snippets ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("duong van chan snippets") or ("dung java java snippets"))) or ("locating bug code snippets"))*.