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