Perhaps you should try some spelling variations:
"ong sach java slippers" » "ong sach va slippers", "cong sach java slippers", "song sach java slippers", "duong sach java slippers", "ong sach java slippery", "ong sach java grippers"
"dung java java snippets" » "dung va java snippets"
"locating bug code snippets" » "locating bung code snippets", "locating bugs code snippets", "locating bug core 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: (((("ong sach java slippers") or ("dung java java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("ong sach java slippers") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( ong sach java slippers ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("ong sach java slippers") or ("dung java java snippets"))) or ("locating bug code snippets"))*.