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"
"dung cfd code snippets" » "dung cho code snippets", "dung cua code snippets", "dung co code snippets", "dung cfd 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: (((("dung trinh toan snippets") or ("dung cfd code snippets"))) or ("locating bug code snippets"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((("dung trinh toan snippets") OR ("dung cfd code snippets"))) OR ("locating bug code snippets")).
• Removing quotes may allow a broader search: (((( dung trinh toan snippets ) or ( dung cfd code snippets ))) or ( locating bug code snippets )).
• Adding a wildcard symbol may retrieve word variants: (((("dung trinh toan snippets") or ("dung cfd code snippets"))) or ("locating bug code snippets"))*.