Perhaps you should try some spelling variations:
"dung trinh toan snippets" » "dung tinh toan snippets", "dong trinh toan snippets", "cong trinh toan snippets", "dung thanh toan snippets", "dung trinh han snippets"
"using c code snippets" » "using lc code snippets", "using a code snippets", "using _ code snippets", "using cfd code 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 c code snippets\") OR (\"dung trinh toan snippets\"))) OR (\"locating bug code snippets\"))~".
• Removing quotes may allow a broader search: (((( using c code snippets ) OR ( dung trinh toan snippets ))) OR ( locating bug code snippets ))~.
• Adding a wildcard symbol may retrieve word variants: (((("using c code snippets") OR ("dung trinh toan snippets"))) OR ("locating bug code snippets"))*.