Perhaps you should try some spelling variations:
"using java core snippets" » "using data core snippets"
"dung dat lieu snippets" » "dung va lieu snippets", "dung tai lieu snippets", "dung vat lieu snippets", "dung da lieu snippets", "dung dat hieu 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.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"using java core snippets\") OR (\"dung dat lieu snippets\"))) OR (\"locating bug code snippets\"))~".
• Removing quotes may allow a broader search: (((( using java core snippets ) OR ( dung dat lieu snippets ))) OR ( locating bug code snippets ))~.
• Adding a wildcard symbol may retrieve word variants: (((("using java core snippets") OR ("dung dat lieu snippets"))) OR ("locating bug code snippets"))*.