Perhaps you should try some spelling variations:
"tu mach trinh cau - so giao" » "tu hanh trinh cau - so giao", "tu sach tranh cau - so giao", "tu mach tich cau - so giao", "tu mach trinh chat - so giao", "tu mach trinh chao - so giao", "tu mach trinh tu - so giao", "tu mach trinh cau - so giai", "tu mach trinh cau - hoc giao", "tu cach trinh cau - so giao", "tu manh trinh cau - so giao", "tu hach trinh cau - so giao"
"so sach lich su - so giao" » "so sach kinh su - so giao", "so tich lich su - so giao", "so mach tich su - so giao", "so sanh lich su - so giao", "bo sach lich su - so giao", "co sach lich su - so giao", "so sach lich su - so giai", "so sach lich su - hoc giao"

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("so sach lich su - so giao") or ("tu mach trinh cau - so giao"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("so sach lich su - so giao") OR ("tu mach trinh cau - so giao")).
• Removing quotes may allow a broader search: (( so sach lich su - so giao ) or ( tu mach trinh cau - so giao )).
• Adding a wildcard symbol may retrieve word variants: (("so sach lich su - so giao") or ("tu mach trinh cau - so giao"))*.