Perhaps you should try some spelling variations:
"trinh van canh snippets" » "trinh van code snippets", "trinh han canh snippets", "trinh quan canh snippets", "trinh toan canh snippets", "trinh van anh snippets", "trinh van hanh snippets", "trinh van manh 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: (((("dung java java snippets") or ("trinh van canh snippets"))) or ("locating bug core snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("dung java java snippets") OR ("trinh van canh snippets"))) OR ("locating bug core snippets")).
• Removing quotes may allow a broader search: (((( dung java java snippets ) or ( trinh van canh snippets ))) or ( locating bug core snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dung java java snippets") or ("trinh van canh snippets"))) or ("locating bug core snippets"))*.