Perhaps you should try some spelling variations:
"sach ngan java slippers" » "sach ngon java slippers", "sach nha java slippers", "sach han java slippers", "sach ngu java slippers", "sach ngan java slippery", "sach ngan 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: (((("sach ngan 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: (((("sach ngan java slippers") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( sach ngan java slippers ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("sach ngan java slippers") or ("dung java java snippets"))) or ("locating bug code snippets"))*.