Perhaps you should try some spelling variations:
"su sach trien nghiep ye hoc" » "su sach trinh nghien ye hoc", "su sach vien nghien ye hoc", "su sach bien nghien ye hoc", "su sach tien nghiep ye hoc", "su sach tren nghiep ye hoc", "su sach thieu nghiep ye hoc", "su sach trien nghiep ke hoc", "su sach trien nghiep y hoc", "su sach trien nghiep he hoc", "vu sach trien nghiep ye hoc", "su sach trien nghiep te hoc", "su sach trien nghiep de hoc"
"so sach tham nghiem d hoc" » "so sach trac nghiem d hoc", "so sach thuc nghiem d hoc", "so sach thi nghiem d hoc", "so sach nha nghiem d hoc", "so sach tham nghiem de hoc", "so sach tham nghiem do hoc", "so sach tham nghiem _ hoc", "so sanh tham nghiem d hoc", "bo sach tham nghiem d hoc", "co sach tham nghiem d hoc", "so sach tham nghiem du hoc", "so sach tham nghiem ad hoc"

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: (("su sach trien nghiep ye hoc") or ("so sach tham nghiem d hoc"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("su sach trien nghiep ye hoc") OR ("so sach tham nghiem d hoc")).
• Removing quotes may allow a broader search: (( su sach trien nghiep ye hoc ) or ( so sach tham nghiem d hoc )).
• Adding a wildcard symbol may retrieve word variants: (("su sach trien nghiep ye hoc") or ("so sach tham nghiem d hoc"))*.