Perhaps you should try some spelling variations:
"using java code snippets" » "using data code snippets"
"duong so robot snippets" » "duong co robot snippets", "duong o robot snippets", "dung so robot snippets", "duong cho robot snippets", "duong tao robot snippets", "duong voi robot snippets"
"locating bug core snippets" » "locating bug code 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: (((("using java code snippets") or ("duong so robot snippets"))) or ("locating bug core snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("using java code snippets") OR ("duong so robot snippets"))) OR ("locating bug core snippets")).
• Removing quotes may allow a broader search: (((( using java code snippets ) or ( duong so robot snippets ))) or ( locating bug core snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("using java code snippets") or ("duong so robot snippets"))) or ("locating bug core snippets"))*.