Perhaps you should try some spelling variations:
"trac cong trinh slippers" » "tran cong trinh slippers", "tra cong trinh slippers", "trao cong trinh slippers", "trac cong trinh slippery", "trac cong trinh 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: (((("trac cong trinh slippers") or ("dung java java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("trac cong trinh slippers") OR ("dung java java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( trac cong trinh slippers ) or ( dung java java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("trac cong trinh slippers") or ("dung java java snippets"))) or ("locating bug code snippets"))*.