Perhaps you should try some spelling variations:
"dong tin cong snippets" » "dong tin code snippets", "thong tin cong snippets", "luong tin cong snippets", "dong kinh cong snippets", "dong tien cong snippets", "dong tan cong snippets", "dong thien cong 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 tin cong 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 tin cong snippets") OR ("dung java java snippets"))) OR ("locating bug core snippets")).
• Removing quotes may allow a broader search: (((( dong tin cong snippets ) or ( dung java java snippets ))) or ( locating bug core snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dong tin cong snippets") or ("dung java java snippets"))) or ("locating bug core snippets"))*.