Perhaps you should try some spelling variations:
"van dung open snippets" » "van dung code snippets", "van dung tren snippets", "van dung nen snippets", "van dung len snippets", "van dong open snippets", "xay dung open snippets", "tin dung open snippets"
"locating bug core snippets" » "locating bug code snippets"
"using java java snippets" » "using data java snippets"

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (((("van dung open snippets") or ("using java java snippets"))) or ("locating bug core snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("van dung open snippets") OR ("using java java snippets"))) OR ("locating bug core snippets")).
• Removing quotes may allow a broader search: (((( van dung open snippets ) or ( using java java snippets ))) or ( locating bug core snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("van dung open snippets") or ("using java java snippets"))) or ("locating bug core snippets"))*.