Perhaps you should try some spelling variations:
"using java core snippets" » "using data core snippets"
"dan hoc trac snippets" » "dan hoi trac snippets", "dan hoc truc snippets", "dan hoc thuc snippets", "van hoc trac snippets", "dan toc trac snippets", "dai hoc trac 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 ("dan hoc trac snippets"))) OR ("locating bug code snippets"))~.
• Removing quotes may allow a broader search: (((( using java core snippets ) or ( dan hoc trac snippets ))) or ( locating bug code snippets ))~.
• Adding a wildcard symbol may retrieve word variants: (((("using java core snippets") or ("dan hoc trac snippets"))) or ("locating bug code snippets"))*.