Perhaps you should try some spelling variations:
"locating bug core snippets" » "locating bug code snippets"
"python using java snippets" » "python using data snippets"
"dan thi luan snippets" » "dan thi lan snippets", "dan thi xuan snippets", "dan thi loan snippets", "dang thi luan snippets", "tran thi luan snippets", "dinh thi luan 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: (((("dan thi luan snippets") or ("python using java snippets"))) or ("locating bug core snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("dan thi luan snippets") OR ("python using java snippets"))) OR ("locating bug core snippets")).
• Removing quotes may allow a broader search: (((( dan thi luan snippets ) or ( python using java snippets ))) or ( locating bug core snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dan thi luan snippets") or ("python using java snippets"))) or ("locating bug core snippets"))*.