Perhaps you should try some spelling variations:
"doi hoc cong snippets" » "doi hoc code snippets", "doi hoc co snippets", "doi cac cong snippets", "doi hoc dung snippets", "doi hoac cong snippets", "dai hoc cong snippets", "hoi hoc cong snippets"
"locating bug core snippets" » "locating bug code snippets"
"python using java snippets" » "python using data 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 hoc cong 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 hoc cong snippets"))) OR ("locating bug core snippets")).
• Removing quotes may allow a broader search: (((( python using java snippets ) or ( doi hoc cong snippets ))) or ( locating bug core snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("python using java snippets") or ("doi hoc cong snippets"))) or ("locating bug core snippets"))*.