Perhaps you should try some spelling variations:
"tu sach trinh thiet ban hoc" » "tu sach trinh viet ban hoc", "tu sach trinh thi ban hoc", "tu sach tranh thiet ban hoc", "tu hanh trinh thiet ban hoc", "tu sach kinh thiet ban hoc", "tu sach trinh thien ban hoc", "tu sach trinh thien bang hoc", "tu sach trinh thiet bi hoc", "thu sach trinh thiet ban hoc", "su sach trinh thiet ban hoc", "te sach trinh thiet ban hoc", "tu sach trinh thiet bang hoc", "tu sach trinh thiet van hoc", "tu sach trinh thiet bai hoc"
"tu sach tac nghiep va hoc" » "tu sach cac nghiep va hoc", "tu sach trac nghiem va hoc", "tu sach sach nghiep va hoc", "tu sach tac nghiep vu hoc", "tu sach bac nghiep va hoc", "tu sach tai nghiep va hoc", "tu sach tham nghiep va hoc", "thu sach tac nghiep va hoc", "su sach tac nghiep va hoc", "te sach tac nghiep va hoc", "tu sach tac nghiep van 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: (("tu sach trinh thiet ban hoc") or ("tu sach tac nghiep va hoc"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("tu sach trinh thiet ban hoc") OR ("tu sach tac nghiep va hoc")).
• Removing quotes may allow a broader search: (( tu sach trinh thiet ban hoc ) or ( tu sach tac nghiep va hoc )).
• Adding a wildcard symbol may retrieve word variants: (("tu sach trinh thiet ban hoc") or ("tu sach tac nghiep va hoc"))*.