Perhaps you should try some spelling variations:
"using java core snippets" » "using data core snippets"
"dung thong tin snippets" » "dung thuong tin snippets", "dung trong tin snippets", "dong thong tin snippets", "dung thong tinh snippets"
"locating bug code snippets" » "locatinhg bug code snippets", "locating bung code snippets", "locating bugs code 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: (((("using java core snippets") or ("dung thong tin snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("using java core snippets") OR ("dung thong tin snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( using java core snippets ) or ( dung thong tin snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("using java core snippets") or ("dung thong tin snippets"))) or ("locating bug code snippets"))*.