Perhaps you should try some spelling variations:
"dong trinh doc snippets" » "cong trinh doc snippets", "dong tinh doc snippets", "dong tranh doc snippets", "dong trinh do snippets", "dong trinh hoa snippets", "dong trinh co snippets"
"data using java snippets" » "data using data 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: (((("dong trinh doc snippets") or ("data using java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("dong trinh doc snippets") OR ("data using java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( dong trinh doc snippets ) or ( data using java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dong trinh doc snippets") or ("data using java snippets"))) or ("locating bug code snippets"))*.