Perhaps you should try some spelling variations:
"using java code snippets" » "using data code snippets"
"duc van zhang snippets" » "duc van khang snippets", "duc van hang snippets", "duc van thang snippets", "duc va zhang snippets", "duc tan zhang snippets", "duc manh zhang snippets"
"locating bug core snippets" » "locating bug code snippets"

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

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