Perhaps you should try some spelling variations:
"using java core snippets" » "using data core snippets"
"van toan doan snippets" » "van toan doanh snippets", "van tan doan snippets", "van tran doan snippets", "van tuan doan snippets", "van thanh doan snippets"
"locating bug code snippets" » "locating bung code snippets", "locating bugs 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 core snippets") or ("van toan doan snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("using java core snippets") OR ("van toan doan snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( using java core snippets ) or ( van toan doan snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("using java core snippets") or ("van toan doan snippets"))) or ("locating bug code snippets"))*.