Perhaps you should try some spelling variations:
"luan doanh c snippets" » "luat doanh c snippets", "luan danh c snippets", "nhuan doanh c snippets", "luan doanh co snippets", "luan doanh _ snippets", "luan doanh cua snippets"
"python using java snippets" » "python 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: (((("luan doanh c snippets") or ("python using java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("luan doanh c snippets") OR ("python using java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( luan doanh c snippets ) or ( python using java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("luan doanh c snippets") or ("python using java snippets"))) or ("locating bug code snippets"))*.