Perhaps you should try some spelling variations:
"dong cau chap snippets" » "dong cau code snippets", "cong cau chap snippets", "dong cac chap snippets", "dong mau chap snippets", "dong cau cham snippets", "dong cau chan snippets", "dong cau phap snippets"
"locating bug core snippets" » "locating bug code snippets"
"dung java java snippets" » "dung va java 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: (((("dong cau chap snippets") or ("dung java java snippets"))) or ("locating bug core snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("dong cau chap snippets") OR ("dung java java snippets"))) OR ("locating bug core snippets")).
• Removing quotes may allow a broader search: (((( dong cau chap snippets ) or ( dung java java snippets ))) or ( locating bug core snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dong cau chap snippets") or ("dung java java snippets"))) or ("locating bug core snippets"))*.