Perhaps you should try some spelling variations:
"cong nghe kinh hoc giao trinh" » "cong nghe sinh hoc giao trinh", "cong nghiem kinh hoc giao trinh", "cong nghiep kinh hoc giao trinh", "cong nghe kinh hoc cao trinh", "cong nghe hinh hoc giao trinh", "cong nghe tinh hoc giao trinh", "cong nghe tin hoc giao trinh"
"cong nghe dinh hoc OR sinh hoc giao trinh" » "cong nghe hinh hoc OR sinh hoc giao trinh", "cong nghe tinh hoc OR sinh hoc giao trinh", "cong nghe dich hoc OR sinh hoc giao trinh"

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: (("cong nghe ((dinh hoc) OR (sinh hoc)) giao trinh") or ("cong nghe kinh hoc giao trinh"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("cong nghe ((dinh hoc) OR (sinh hoc)) giao trinh") OR ("cong nghe kinh hoc giao trinh")).
• Removing quotes may allow a broader search: (( cong nghe ((dinh hoc) OR (sinh hoc)) giao trinh ) or ( cong nghe kinh hoc giao trinh )).
• Adding a wildcard symbol may retrieve word variants: (("cong nghe ((dinh hoc) OR (sinh hoc)) giao trinh") or ("cong nghe kinh hoc giao trinh"))*.