Perhaps you should try some spelling variations:
"doc trinh java slippers" » "doc tinh java slippers", "doi trinh java slippers", "hoc trinh java slippers", "doc trinh java slippery", "doc trinh 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: (((("doc trinh 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: (((("doc trinh java slippers") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( doc trinh java slippers ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("doc trinh java slippers") or ("dung java java snippets"))) or ("locating bug code snippets"))*.