Perhaps you should try some spelling variations:
"locating bug core snippets" » "locating bug code snippets"
"python using java snippets" » "python using data snippets"
"doi na zhang snippets" » "doi nam thang snippets", "doi tao zhang snippets", "doi yan zhang snippets", "doi nam zhang snippets", "doi va zhang snippets", "doi xa zhang 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: (((("python using java snippets") or ("doi na zhang snippets"))) or ("locating bug core snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("python using java snippets") OR ("doi na zhang snippets"))) OR ("locating bug core snippets")).
• Removing quotes may allow a broader search: (((( python using java snippets ) or ( doi na zhang snippets ))) or ( locating bug core snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("python using java snippets") or ("doi na zhang snippets"))) or ("locating bug core snippets"))*.