Perhaps you should try some spelling variations:
"dong truyen du snippets" » "cong truyen du snippets", "tang truyen du snippets", "dong chuyen du snippets", "dong truyen dan snippets", "dong truyen mau snippets", "dong truyen cua snippets"
"using java code snippets" » "using data code snippets", "using java core snippets"
"locating bug code snippets" » "locating bug core snippets", "locating bung code snippets", "locating bugs 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 ("dong truyen du snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("using java code snippets") OR ("dong truyen du snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( using java code snippets ) or ( dong truyen du snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("using java code snippets") or ("dong truyen du snippets"))) or ("locating bug code snippets"))*.