Perhaps you should try some spelling variations:
"python using java snippets" » "python using data snippets"
"van thi chap snippets" » "van thi phap snippets", "van thi cham snippets", "van thi cap snippets", "van tai chap snippets", "dan thi chap snippets", "van thu chap 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: (((("van thi chap snippets") or ("python using java snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("van thi chap snippets") OR ("python using java snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( van thi chap snippets ) or ( python using java snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("van thi chap snippets") or ("python using java snippets"))) or ("locating bug code snippets"))*.