Perhaps you should try some spelling variations:
"khoa hoc minh slippery" » "hoa hoc minh slippery", "khoa hoc sinh slippery", "khoa hoc kinh slippery", "khoa hoc vinh slippery", "khoa hoc minh slippers"
"python using a snippets" » "python using a slippers"
"locating bug code snippets" » "locating bug code slippers", "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: (((("khoa hoc minh slippery") or ("python using a snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("khoa hoc minh slippery") OR ("python using a snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( khoa hoc minh slippery ) or ( python using a snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("khoa hoc minh slippery") or ("python using a snippets"))) or ("locating bug code snippets"))*.