Perhaps you should try some spelling variations:
"using java core snippets" » "using data core snippets"
"con toan hoc snippets" » "cong toan hoc snippets", "mon toan hoc snippets", "con than hoc snippets", "con toan khoa snippets", "con van hoc snippets", "con hoa hoc snippets"
"locating bug code snippets" » "locating bung code snippets", "locating bugs code snippets"

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (((("using java core snippets") OR ("con toan hoc snippets"))) OR ("locating bug code snippets"))~.
• Removing quotes may allow a broader search: (((( using java core snippets ) or ( con toan hoc snippets ))) or ( locating bug code snippets ))~.
• Adding a wildcard symbol may retrieve word variants: (((("using java core snippets") or ("con toan hoc snippets"))) or ("locating bug code snippets"))*.